Multilayer substrate with inner capacitors

ABSTRACT

A multilayer substrate with inner capacitors comprising a dielectric layer sandwiched between upper and lower insulating layers, a couple of printed electrodes in desired patterns within the thickness of the dielectric layer so as to form each capacitor at the portion of the dielectric layer corresponding to the electrodes, and a couple of leading terminals on one surface of the insulating layer, which communicate with the electrodes, the multilayer substrate being characterized in that the dielectric layer is composed of a ceramic composition mainly comprising MTiO 3  -based ceramics (M represents one or several of Ba, Ca, Mg, La, Sr and Nd) and the insulating layer is composed of a ceramic composition mainly comprising MgO-SiO 2  -CaO-based ceramics, which is defined by an area surrounded by the lines connecting points A, B, C, D, E, F and G as shown in FIG. 1 and listed below, wherein X, Y and Z respectively represent weight percent values of MgO, SiO 2  and CaO at points A, B, C, D, E, F and G. 
     
         ______________________________________                                    
 
    
            X            Y     Z                                               
______________________________________                                    
A        60             40     0                                          
B        40             60     0                                          
C        30             60    10                                          
D        30             50    20                                          
E        20             50    30                                          
F        40             30    30                                          
G        60             30    10                                          
______________________________________                                    
 
     With this multilayer substrate, the dielectric layer and the insulating layers can be co-fired. Therefore, cracking between the layers can be prevented and the superior insulation characteristics, such as insulation resistance and dielectric breakdown voltage, of the substrate can be maintained.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a multilayer substrate with innercapacitors, which has capacitors, resistors and electric wiringconductor sections, and more particularly to a multilayer substrate withinner capacitors made by co-firing insulating layers and dielectriclayers.

2. Prior Art

These days, a variety of electronic elements are being made smaller insize and mounted higher in density by use of semiconductor integratedcircuit devices, such as ICs and LSIs. To cope with this trend,insulating substrates on which such semiconductor integrated circuitdevices are mounted are required to be made smaller in size and higherin density. To meet these requirements, electric wires are being madethinner and multi-layered to increase density, and passive elements inelectronic circuits, such as capacitors and resistors, are made in theform of chips. In addition, these miniaturized passive elements areattached to the electric wiring conductor sections provided on bothsides of an insulating substrate, a practical use of both-side mountingof elements.

However, the significant advancement of semiconductor materials requireselectric elements to be made far smaller in size and mounted far higherin density. The above-mentioned miniaturized passive elements, however,cannot fully meet the requirements.

To meet the requirements, a composite ceramic substrate has beenproposed. The capacitor section (passive element) of this proposedsubstrate is printed as a thick film on an insulating layer (greensheet) by screen printing for example. Together with electrode sectionsand internal wiring conductor sections which are printed on theinsulating layer by the same method as described above, the capacitorsection is co-fired with the above-mentioned insulating layer. Otherelectric wiring conductor sections and resistor sections are thenprinted by the above-mentioned screen printing method on the insulatinglayer thus fired. The conductor sections and resistor sections are firedto obtain a hybrid composite ceramic substrate, thereby making electricelements smaller in size and higher in density. (Refer to JapanesePatent Publication No. 63-55795.)

In the case of this conventional composite ceramic substrate, when thedielectric layer made of a ceramics mainly comprising barium titanate(BaTiO₃) for example is laminated with an insulating layer mainlycomprising alumina which is high in mechanical strength, chemicallystable and superior in insulation performance, and when the aluminaceramics of the insulating layer is co-fired with the ceramicscomprising barium titanate of the dielectric layer, with the twoceramics being in contact with each other, these ceramics react witheach other and the desired characteristics of the dielectric layercannot be obtained. In addition, it is difficult to coincide the firingtemperature of the ceramics comprising the alumina of the insulatinglayer with that of the ceramics comprising the barium titanate of thedielectric. layer. Furthermore, cracks are generated in the dielectriclayer due to the difference in thermal expansion coefficient between theinsulating layer and the dielectric layer, thereby reducing theinsulation resistance and dielectric breakdown voltage of the capacitorsection.

SUMMARY OF THE INVENTION

In order to eliminate the above-mentioned drawbacks, the object of thepresent invention is to provide a multilayer substrate whose dielectricand insulating layers can be co-fired. More particularly, the dielectriclayer is available in three types: a high-capacitance type, atemperature compensation type and a mixture type of the two. Theinsulating layer of the substrate is available in two types: a type withsuperior high-frequency insulation performance and a type with higherstrength and superior high-frequency insulation performance.Accordingly, the present invention provides first to fourth inventionsdepending on the combination of the above-mentioned three types ofdielectric layers and two types of insulating layers. The firstinvention is a combination of a dielectric layer with high capacitanceand insulating layers with superior high-frequency insulationperformance. The second invention is a combination of a dielectric layerwith high temperature compensation performance and insulating layerswith superior high-frequency insulation performance. The third inventionis a combination of dielectric layers with high capacitance and hightemperature compensation performance, and insulating layers withsuperior high-frequency insulation performance. The fourth invention isa combination of dielectric layers of the third invention and insulatinglayers which are strengthened by improving the insulating layers of thefirst to third inventions. The objects of the four inventions can beaccomplished by using the following two effects common to the fourinventions. Co-firing of the dielectric and insulating layers are madepossible by setting the thermal expansion coefficient of the insulatinglayer close to that of the dielectric layer, and the firing temperaturecan be set lower than that of the conventional dielectric or insulatinglayer. In particular, the insulating layer of the fourth invention isstrengthened and its firing temperature can be made lower than those ofthe insulating layers of the first to third inventions.

The dielectric layer commonly used in the first to fourth inventions ismade of a ceramic composition mainly comprising MTiO₃ -based ceramicsdescribed later. The insulating layer is generally made of a ceramiccomposition mainly comprising MgO-SiO₂ -CaO-based ceramics. Theinsulating layer of the fourth invention also includes Al₂ O₃ as thefourth component in addition to the above-mentioned three components.These insulating layers comprising the three components indicated byspecific areas surrounded by lines connecting six to seven points in theternary phase diagrams of these inventions. The further addition of Al₂O₃ indicates a constant additional polymerization range. The first tofourth inventions are detailed below referring to the correspondingexample drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a ternary phase diagram for MgO-SiO₂ -CaO illustrating thecomposition areas of the insulating layer used in the genus inventionfor the multilayer substrates with inner capacitors of the first tofourth inventions;

FIG. 2 is a ternary phase diagram illustrating the composition area ofthe insulating layer of the first invention;

FIG. 3 is a diagram similar to FIG. 2, illustrating the composition areaof the insulating layer of the second invention;

FIG. 4 is a diagram similar to FIG. 2, illustrating the composition areaof the insulating layer of the third invention;

FIG. 5 is a diagram similar to FIG. 2, illustrating the composition areaof the insulating layer of the fourth invention;

FIG. 6 is a cross section of a circuit substrate common to the first andsecond inventions; and

FIG. 7 is a cross section of a circuit substrate common to the third andfourth inventions.

DETAILED DESCRIPTION OF THE INVENTION

The genus invention and the first to fourth inventions are detailedbelow in that order. For easy understanding, the relations among theinventions, claims and drawings are generally explained below. Claim 1and FIG. 1 that corresponds to claim 1 are applicable to all thesurrounded areas of the MgO-SiO₂ -CaO-based ceramics of the genusinvention for all the inventions. Claims 2 and 4 and FIG. 2 apply to thefirst invention. Claims 5 to 7 and FIG. 3 apply to the second invention.Claims 8 to 10 and FIG. 4 apply to the third invention. Claims 11 to 14and FIG. 5 apply to the fourth invention.

The genus invention is a multilayer substrate with inner capacitorscomprising a dielectric layer sandwiched between an upper and lowerinsulating layers, a couple of printed electrodes in desired patternswithin the thickness of the dielectric layer so as to form eachcapacitor at the portion of the dielectric layer corresponding to theelectrodes, and a couple of leading terminals on one surface of theinsulating layer, which communicate with the electrodes. The substrateis characterized in that the dielectric layer is composed of a ceramiccomposition mainly comprising MTiO₃ -based ceramics (M represents one orseveral of Ba, Ca, Mg, La, Sr and Nd) and the insulating layer iscomposed of a ceramic material mainly comprising MgO-SiO₂ -CaO-basedceramics, which is defined by an area surrounded by the lines connectingpoints A, B, C, D, E, F and G as shown in FIG. 1 and listed below,wherein X, Y and Z respectively represent weight percent values of MgO,SiO₂ and Cao at points A, B, C, D, E, F and G.

    ______________________________________                                               X            Y     Z                                                   ______________________________________                                        A        60             40     0                                              B        40             60     0                                              C        30             60    10                                              D        30             50    20                                              E        20             50    30                                              F        40             30    30                                              G        60             30    10                                              ______________________________________                                    

For easy understanding of the genus invention, the first and fourthinventions are detailed first as described below.

The object of the first invention is to provide a multilayer substratewith inner capacitors having high electrostatic capacitance by co-firinginsulating layers mainly comprising MgO-SiO₂ -CaO-based ceramics havingsuperior high-frequency insulation performance with a dielectric layermainly comprising barium titanate (BaTiO₃) having a high dielectricconstant.

More specifically, the insulating layers of the multilayer substratewith inner capacitors of the first invention, between which a capacitorsection being composed of a dielectric layer mainly comprising bariumtitanate (BaTiO₃) is sandwiched, are insulating layers mainly comprisingMgO-SiO₂ -CaO-based ceramics in the area surrounded by the linesconnecting points A₁, B₁. E, F and G as shown in FIG. 2. The insulatinglayer includes at least one crystal phase of forsterite (Mg₂ SiO₄),monticellite (CaMgSiO₄) or akermanite (Ca₂ MgSi₂ O₇). The dielectriclayer and the insulating layers, between which the capacitor sectionbeing composed of the dielectric layer portions and electrode layers aresandwiched, can be co-fired. X, Y and Z respectively represent theweight percent values of MgO, SiO₂ and CaO.

    ______________________________________                                               X            Y     Z                                                   ______________________________________                                        A.sub.1  60             36     4                                              B.sub.1  46             50     4                                              E        20             50    30                                              F        40             30    30                                              G        60             30    10                                              ______________________________________                                    

In the composition of the above-mentioned insulating layer shown in FIG.2, if the content of MgO exceeds 60 weight %, the firing temperaturebecomes 1360° C. or more. This prevents the insulating layer from beingco-fired with the dielectric layer and causes MgO to deposit, reducingresistance against humidity. If the content of MgO is less than 20weight %, the firing temperature becomes 1220° C. or less. This alsoprevents the insulating layer from being co-fired with the dielectriclayer.

If the content of SiO₂ exceeds 50 weight %, the thermal expansioncoefficient of the insulating layer reduces. Due to the difference inthermal expansion coefficient between the insulating layer and thedielectric layer, cracks are caused in the dielectric layer and thepredetermined dielectric characteristics cannot be obtained. If thecontent of SiO₂ is less than 30 weight %, the firing temperature becomes1360° C. or more. This prevents the insulating layer from being co-firedwith the dielectric layer.

If the content of CaO exceeds 30 weight % or is less than 4 weight %,the reactivity of CaO with the ceramics comprising barium titanatebecomes significantly high. This prevents generation of any dielectriclayer having the predetermined characteristics. If the content of CaOexceeds 30 weight %, calcium silicate, such as CaSiO₃ or Ca₂ SiO₄,deposits, thereby reducing the resistance against humidity.

Therefore, the composition of the above-mentioned insulating layer isrestricted within the area surrounded by the lines connecting points A₁,B₁, E, F and G as shown in FIG. 2.

By making adjustment so that the main components, MgO, SiO₂ and CaO, ofthe insulating layers, between which the capacitor section issandwiched, are within the area surrounded by the lines connectingpoints A₁, B₁, E, F and G as shown in FIG. 2, the insulating materialcan be co-fired with the dielectric material comprising barium titanate(BaTiO₂) at 1240° to 1340° C. (the firing temperature range of thedielectric material). In addition to the crystal phase of forsterite, atleast one crystal phase of monticellite (CaMgSiO₄) or akermanite (Ca₂MgSi₂ O₇) is formed. The thermal expansion coefficients of the lattertwo crystal phases differ from that of the crystal phase of forsterite.

EXAMPLE 1

The multilayer substrate with inner capacitors of the first invention isdetailed below taking an example shown in FIG. 6.

FIG. 6 is a cross section of an example of a multilayer substrate commonto the first and second inventions.

Referring to FIG. 6, numeral 1 represents a insulating layer, numeral 2represents a capacitor section, numeral 3 represents an electric wiringconductor. The capacitor section 2 is composed of dielectric layerportions 4 and electrode layers 5 laminated alternately.

The insulating layer 1 is made by mixing ceramic material powdercomprising MgO, SiO₂ and CaO so that its composition is within the areasurrounded by the lines connecting points A₁, B₁, E, F and G as shown inFIG. 2 and by calcining the mixture at 1100° to 1300° C. The calcinedsubstance is pulverized into ceramic powder and mixed with appropriateorganic binders, dispersing agents, plasticizers and solvents to formslurry. The slurry is processed into a sheet by a known method such asthe doctor blade method. A plurality of the green sheets are laminatedto form the insulating layer 1.

The capacitor section 2 is made as follows: the dielectric materialpowder mainly comprising BaTiO₃ is mixed with appropriate organicbinders, dispersing agents, plasticizers and solvents to form slurry.The slurry is processed into a sheet by a known method such as the slipcast method. On the obtained dielectric green sheet, silver-palladium(Ag-Pd) alloy paste for example and mixed with appropriate solvents isprinted by the screen printing method according to the predeterminedelectrode patterns to form the electrode layer 5. To obtain continuitybetween the top and bottom surfaces of the insulating layer 1 andcapacitor section 2, through-hole sections 6 are formed by punching thegreen sheets of the insulating and dielectric layers. In thethrough-hole section 6, the above-mentioned alloy paste is filled.

The above-mentioned green sheets of the insulating and dielectric layersare respectively laminated and pressed at heating. The obtainedlaminations are subjected to a binder burnout process at 200° to 400°C., then co-fired at 1240° to 1340° C. As a result, a multilayersubstrate with the inner capacitor section 2 is obtained.

Electric wiring conductor patterns are formed using Ag-Pd-based alloypaste on the surface of the fired insulating layer 1 by the screenprinting method. When required, resistor patterns are formed using pastemainly comprising ruthenium oxide (RuO₂) by the screen printing method.The substrate is then fired at about 850° C. in the air to obtain amultilayer substrate with inner capacitors and resistors 7.

When using paste mainly comprising copper (Cu) for the electric wiringconductor patterns, paste mainly comprising lanthanum boride (LaB₆) andstannic oxide (SnO₂) is applied by printing to form resistor patterns.The resistor patterns are then various setting capacitance values can beset. The sheets are then punched and formed to dielectric sheets of 170mm square.

On the dielectric sheets, Ag-Pd alloy paste is applied by a thick-filmprinting method such as the screen printing method to form electrodepatterns of about 1 to 10 mm square depending on the requiredelectrostatic capacitance.

The through-hole sections formed in the insulating and dielectric sheetsare filled with the Ag-Pd alloy paste by the screen printing method.

A plurality of the dielectric sheets comprising barium titanate aresandwiched between the insulating sheets and pressed at heating. Theobtained laminations are subjected to a binder burnout process at 200°to 400° C. and fired in the air at the temperatures listed in Table 1.

The evaluation samples made described above were checked forshort-circuit between the electrode layers of the capacitor sectionusing an LCR meter. The electrostatic capacitance of the capacitorsection was measured at a frequency of 1 kHz and at an input signallevel of 1.0 Vrms using the LCR fired at about 900° C. in an atmosphereof nitrogen. As a result, a multilayer substrate with inner capacitorssimilar to that described above is obtained.

The first invention is detailed further taking an example of the firstinvention and a contrast example excluded from the scope of firstinvention.

Various types of ceramic material powder comprising MgO, SiO₂ and CaOare mixed and calcined at 1100° to 1300° C. so that the composition ofthe insulating layer has the ratios listed in Table 1. The calcinedsubstance is pulverized to obtain the desired particle size. Appropriateorganic binders and solvents are then added to the obtained materialpowder to form slurry. The slurry is processed by the doctor blademethod to form a green sheet of 200 μm in thickness. The green sheet isthen punched to obtain insulating sheets of 170 mm square.

The ceramic material powder mainly comprising barium titanate (BaTiO₃)is mixed with appropriate binders and solvents added to form slurry. Theslurry is processed by the slip cast method to form green sheets of 20to 60 μm in thickness so that meter according to the JIS C 5102standards. Relative permittivity (ε_(r)) was calculated from theelectrostatic capacitance. The electrostatic capacitance values weremeasured between -55° C. and 125° C. The change ratio of theelectrostatic capacitance values were calculated as temperaturecoefficients (TCC). The insulation resistance value of the capacitorsection was measured 60 seconds after 25 V DC was applied. Thedielectric breakdown voltage of the capacitor section was measured asthe voltage value obtained in a moment the leak current value exceeded1.0 mA while voltage was applied across the terminals of the capacitorsection at a boosting speed of 100 V/second.

The evaluation samples were used for X-ray diffraction of the crystalphase of the insulating layer. The crystal phase was identifiedaccording to the X-ray diffraction pattern on the surface of theevaluation sample. The thermal expansion coefficients of the insulatingand dielectric layers were obtained by measuring the average thermalexpansion coefficients in the temperature range between 40° and 800° C.using square rod test pieces (in a square rod form) measuring 3×3×40 mm,having the same compositions as those of the corresponding evaluationsamples and co-fired with the evaluation samples. Table 1 indicates theresults of the measurements.

                                      TABLE 1                                     __________________________________________________________________________    Insulating layer                                                                             Firing                                                                             Thermal expan-                                            Composition    tempera-                                                                           sion coefficient                                          (weight %)     ture 40˜800° C.                                   Sample No.                                                                          MgO                                                                              SiO.sub.2                                                                        CaO                                                                              (°C.)                                                                       (1/°C. × 10.sup.-6)                                                      Crystal phase                                     __________________________________________________________________________    *1    62 34  4 1400 12.1    Mg.sub.2 SiO.sub.4,MgO                            *2    62 28 10 1400 12.2    Mg.sub.2 SiO.sub.4,MgO                            *3    60 38  2 1360 11.8    Mg.sub.2 SiO.sub.4,MgO                             4    60 36  4 1340 11.8    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4                   5    60 30 10 1320 11.9    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4                   6    56 40  4 1280 11.7    Mg.sub.2 SiO.sub.4,CaMgSi.sub.2 O.sub.7            7    56 34 10 1260 11.7    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7                                 8    50 46  4 1240 11.5    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7                                            9    50 40 10 1240 11.7    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7                                10    50 34 16 1240 11.8    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7                                11    50 30 20 1280 11.8    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7                                *12   50 28 22 1360 11.9    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7                                *13   48 50  2 1300 10.8    Mg.sub.2 SiO.sub.4,MgSiO.sub.3                    14    46 50  4 1280 11.3    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7                                           15    46 44 10 1260 11.5    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7,CaMgSiO.sub.4                             16    46 40 14 1240 11.7    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7,CaMgSiO.sub.4                             17    46 34 20 1250 11.8    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7,CaMgSiO.sub.4                             *18   44 52  4 1240 10.8    Mg.sub.2 SiO.sub.4,MgSiO.sub.3                    19    40 44 16 1260 11.6    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7                                20    40 40 20 1260 11.8    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7                                21    40 34 26 1260 11.9    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7                                22    40 30 30 1280 11.8    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7                                *23   40 28 32 1320 11.7    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7,MgO                            24    35 50 15 1280 11.3    Mg.sub.2 SiO.sub.4, Ca.sub.2 MgSi.sub.2                                       O.sub.7                                           25    35 45 20 1280 11.5    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7                                26    35 40 25 1260 11.7    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7                                *27   30 52 18 1240 10.8    Mg.sub.2 SiO.sub.4,CaMgSi.sub.2 O.sub.6,                                      Ca.sub.2 MgSi.sub.2 O.sub.7                       28    30 50 20 1250 11.3    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7                                29    30 44 26 1250 11.5    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7                                30    30 40 30 1280 11.6    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7                                *31   30 38 32 1280 11.7    Ca.sub.2 SiO.sub.4,CaMgSiO.sub.4                  32    20 50 30 1280 11.5    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub. 2                                   MgSi.sub.2 O.sub.7                                *33   18 52 30 1220 10.6    CaMgSi.sub.2 O.sub.6, Ca.sub.2 MgSi.sub.2                                     O.sub.7                                           *34   18 50 32 1220 10.8    CaMgSi.sub.2 O.sub.6, Ca.sub.2 MgSi.sub.2                                     O.sub.7                                           __________________________________________________________________________           Dielectric                                                                    layer   Capacitor section                                                     Thermal expan-                                                                        Relative                                                                            Temperature  Dielectric                                         sion coefficient                                                                      permit-                                                                             coefficient                                                                          Insulation                                                                          breakdown                                          40˜800° C.                                                               tivity                                                                              TCC    resistance                                                                          voltage                                     Sample No.                                                                           (1/°C. × 10.sup.-6)                                                      εΓ                                                                    (%)    (Ω)                                                                           (V)    Remarks                              __________________________________________________________________________    *1     12.4    --    --     --    --     Nonmea-                                                                       surable                              *2     12.4    --    --     --    --     Nonmea-                                                                       surable                              *3     12.4    1800   ±30                                                                               10.sup.7                                                                            120                                         4     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500   FIG. 2, A1                            5     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500   FIG. 2, G                             6     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                         7     12.4    2500  <±15                                                                              >10.sup. 10                                                                         >500                                         8     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                         9     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                        10     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                        11     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                        *12    12.4    1900   ±35                                                                               10.sup.8                                                                            250                                        *13    12.4    1950   ±20                                                                               10.sup.7                                                                             80                                        14     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500   FIG. 2, B1                           15     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                        16     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                        17     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                        *18    12.4    2100   ±25                                                                               10.sup.8                                                                            150                                        19     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                        20     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                        21     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                        22     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500   FIG. 2, F                            *23    12.4    1800   ±30                                                                               10.sup.7                                                                            300                                        24     12.4    2500  <±15                                                                              >10.sup. 10                                                                         >500                                        25     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                        26     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                        *27    12.4    1800   ±25                                                                               10.sup.8                                                                            140                                        28     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                        29     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                        30     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500                                        *31    12.4    2300   ±20                                                                               10.sup.9                                                                           >500                                        32     12.4    2500  <±15                                                                              >10.sup.10                                                                          >500   FIG. 2, E                            *33    12.4    2300   ±25                                                                               10.sup.8                                                                           >500                                        *34    12.4    2300   ±25                                                                               10.sup.9                                                                            110                                        __________________________________________________________________________     Samples identified by the numbers marked * are excluded from the scope of     the claims of the present invention.                                     

With the multilayer substrate with inner capacitors of the firstinvention, the insulating layer mainly comprising magnesia, silica andcalcia, and being superior in high-frequency insulation performance canbe co-fired with the dielectric material mainly comprising bariumtitanate without causing reaction between the two. In addition, thethermal expansion coefficient of the insulating layer can be set veryclose to that of the dielectric layer as shown in Table 1. The innercapacitor section can thus have high electrostatic capacitance,insulation resistance and dielectric breakdown voltage without causingcracks in the dielectric layer. As a result, the invention can offer amultilayer substrate with inner capacitors that is miniaturized and highin density, ideally suited for hybrid substrates for example.

The object of the second invention is to provide a multilayer substratewith inner capacitors having stable various characteristics astemperature compensation capacitors, wherein insulating layers mainlycomprising MgO and SiO₂ or MgO, SiO₂ and CaO and having superiorhigh-frequency insulation performance can be co-fired with a dielectricmaterial for temperature compensation. More specifically, the insulatinglayers of the multilayer substrate with inner capacitors of the secondinvention, between which a capacitor section mainly comprising adielectric ceramics for temperature compensation is sandwiched, areinsulating layers mainly comprising magnesia (MgO) and silica (SiO₂) ormagnesia (MgO), silica (SiO₂) and calcia (CaO) in the area surrounded bythe lines connecting points A, B, C, E₁, F and G shown in FIG. 3. Theinsulating layer includes at least one crystal phase of forsterite (Mg₂SiO₄), monticellite (CaMgSiO₄) or akermanite (Ca₂ MgSi₂ O₇). Thedielectric layer and the insulating layers, between which the capacitorsection being composed of the dielectric layer portions and electrodelayers are sandwiched, can be co-fired. X, Y and Z respectivelyrepresent the weight percent values of magnesia (MgO), silica (SiO₂) andcalcia (CaO).

    ______________________________________                                                X           Y     Z                                                   ______________________________________                                        A         60            40     0                                              B         40            60     0                                              C         30            60    10                                              .sub. E.sub.1                                                                           30            40    30                                              F         40            30    30                                              G         60            30    10                                              ______________________________________                                    

In the composition of the above-mentioned insulating layer shown in FIG.3, if the content of MgO exceeds 60 weight %, the firing temperaturebecomes 1400° C. or more. This prevents the insulating layer from beingco-fired with the dielectric layer for temperature compensation. If thecontent of MgO is less than 30 weight %, the insulation resistance valueand dielectric breakdown voltage reduce beyond their practical ranges.

If the content of SiO₂ exceeds 60 weight %, the thermal expansioncoefficient of the insulating layer reduces. Due to the difference inthermal expansion coefficient between the insulating layer and thedielectric layer for temperature compensation, cracks are caused in thedielectric layer for temperature compensation and the insulationresistance value and dielectric breakdown voltage reduce beyond theirpractical ranges. If the content of SiO₂ is less than 30 weight %, thefiring temperature becomes 1400° C. or more. This prevents theinsulating layer from being co-fired with the dielectric layer fortemperature compensation.

If the content of CaO exceeds 30 weight %, the firing temperaturebecomes 1400° C. or more. This prevents the insulating layer from beingco-fired with the dielectric layer for temperature compensation. Even ifthey can be co-fired, calcium silicate, such as CaSiO₃ or Ca₂ SiO₄deposits, thereby reducing the insulation resistance value anddielectric breakdown voltage beyond their practical ranges.

Therefore, the composition of the above-mentioned insulating layer isrestricted within the area surrounded by the lines connecting points A,B, C, E₁, F and G as shown in FIG. 3.

By making adjustment so that the main components, MgO and SiO₂ or MgO,SiO₂ and CaO of the insulating layers, between which the capacitorsection is sandwiched, are within the area surrounded by the linesconnecting points A, B, C, E₁, F and G as shown in FIG. 3, theinsulating material can be co-fired with the dielectric material fortemperature compensation mainly comprising calcium titanate (CaTiO₃),magnesium titanate (MgTiO₄), lanthanum titanate (La₂ Ti₂ O₇), strontiumtitanate (SrTiO₃) or neodymium titanate (Nd₂ Ti₂ O₇) at 1240° to 1340°C. (the firing temperature range of the dielectric material. In additionto the crystal phase of forsterite (Mg₂ SiO₄), at least one crystalphase of enstatite (MgSiO₃), monticellite (CaMgSiO₄) or akermanite (Ca₂MgSi₂ O₇) is formed in the fired insulating layer. The thermal expansioncoefficients of the three crystal phases differ from that of the crystalphase of forsterite. The thermal expansion coefficient of the insulatinglayer can thus be adjusted.

EXAMPLE 2

The multilayer substrate with inner capacitors of the second inventionis detailed below taking an example shown in FIG. 6.

FIG. 6 is a cross section of an example of a multilayer substrate of thesecond invention. Since the structure of the multilayer substrate is thesame as that of the first invention, the explanation of the structure isomitted.

    ______________________________________                                                X           Y     Z                                                   ______________________________________                                        A         60            40     0                                              B         40            60     0                                              C         30            60    10                                              .sub. E.sub.1                                                                           30            40    30                                              F         40            30    30                                              G         60            30    10                                              ______________________________________                                    

X, Y and Z respectively represent weight percent values of magnesia(MgO), silica (SiO₂) and calcia (CaO).

The insulating layer 1 is made by mixing ceramic material powdercomprising MgO and SiO₂ or MgO and SiO₂ and CaO so that its compositionis within the area surrounded by the lines connecting points A, B, C,E₁, F and G as shown in FIG. 3 and by calcining the mixture at 1100° to1300° C. The calcined substance is pulverized into ceramic powder andmixed with appropriate organic binders, dispersing agents, plasticizersand solvents to form slurry. The slurry is processed into green sheetsby a known method such as the doctor blade method. A plurality of thegreen sheets are laminated to form the insulating layer 1.

The capacitor section 2 is made as follows: the dielectric materialpowder for temperature compensation mainly comprising CaTiO₃, Mg₂ TiO₄,La₂ Ti₂ O₇, SrTiO₃ or Nd₂ Ti₂ O₇ is mixed with appropriate organicbinders, dispersing agents, plasticizers and solvents to form slurry.The slurry is processed into green sheets by a known method such as theslip cast method. On the obtained dielectric green sheet,silver-palladium (Ag-Pd) alloy paste for example and mixed withappropriate solvents is printed by the screen printing method accordingto the predetermined electrode patterns to form the electrode layer 5.

To obtain continuity between the top and bottom surfaces of theinsulating layer 1 and capacitor section 2, through-hole sections 6 areformed by punching the green sheets of the insulating and dielectriclayers. In the through-hole sections 6, the above-mentioned alloy pasteis filled.

The above-mentioned green sheets of the insulating and dielectric layersare laminated and pressed at heating respectively. The obtainedlaminations are subjected to a binder burnout process at 200° to 400°C., then co-fired at 1240° to 1340° C. As a result, a multilayersubstrate with the inner capacitor section 2 is obtained.

By the screen printing method, other electric wiring conductor patternsare formed using Ag-Pd-based alloy paste on the surface of the firedinsulating layer 1. When required, resistor patterns are formed usingpaste mainly comprising ruthenium oxide (RuO₂) by the screen printingmethod. The obtained substance is then fired at about 850° C. in the airto obtain a multilayer substrate with inner capacitors and resistors 7.

When using paste mainly comprising copper (Cu) for the electric wiringconductor patterns, paste mainly comprising lanthanum boride (LaB₆) andstannic oxide (SnO₂) is applied by printing to form resistor patterns.The resistor patterns are then fired at about 900° C. in an atmosphereof nitrogen. As a result, a multilayer substrate with inner capacitorssimilar to that described above is obtained.

The second invention is detailed further taking an example of the secondinvention and a contrast example.

Various types of ceramic material powder comprising MgO and SiO₂ or MgOand SiO₂ and CaO are mixed so that the composition of the insulatinglayer has the ratios indicated in Table 2 and calcined at 1100° to 1300°C. The calcined substance is pulverized to obtain the desired particlesize. Appropriate organic binders and solvents are then added to theobtained material powder to form slurry. The slurry is processed by thedoctor blade method to form a green sheet of 200 μm in thickness. Thegreen sheet is then punched to obtain insulating sheets of 170 mmsquare.

The ceramic material powder mainly comprising the dielectric materialfor temperature compensation indicated in Table 2 is mixed withappropriate binder and solvent added to form slurry. The slurry isprocessed by the slip cast method to form green sheets of 20 to 60 μm inthickness so that various capacitance values can be set. The sheets arethen punched and formed to dielectric sheets of 170 mm square.

On the dielectric sheets, Ag-Pd alloy paste is applied by a thick-filmprinting method such as the screen printing method to form electrodepatterns of about 1 to 10 mm square depending on the requiredelectrostatic capacitance.

The through-hole sections formed in the insulating and dielectric sheetsare filled with the Ag-Pd alloy paste by the screen printing method.

A plurality of the dielectric sheets are sandwiched between theinsulating sheets and pressed at heating. The obtained laminations aresubjected to a binder burnout process at 200° to 400° C. in the air andfired in the air at the temperatures indicated in Table 2.

The evaluation samples made described above were checked forshort-circuit between the electrode layers of the capacitor sectionusing an LCR meter. The electrostatic capacitance of the capacitorsection was then measured at a frequency of 1 kHz, at an input signallevel of 1.0 Vrms and at -55° C. to 125° C. using the LCR meteraccording to the JIS C 5102 standards. The change ratios of theelectrostatic capacitance values were calculated as temperaturecoefficients (TCC). In the same way, the resistance value of thecapacitor section was measured 60 seconds after 25 V DC was applied tothe capacitor section. The resistance value was assumed as theinsulation resistance value of the capacitor section. Voltage was alsoapplied across the terminals of the capacitor section at a boostingspeed of 100 V/second and the voltage value obtained in a moment theleak current value exceeded 1.0 mA was measured. The voltage value wasassumed as the dielectric breakdown voltage of the capacitor section.

The evaluation samples were used for X-ray diffraction of the crystalphase of the insulating layer. The crystal phase was identifiedaccording to the X-ray diffraction pattern on the surface of eachevaluation sample. The thermal expansion coefficients of the insulatingand dielectric layers were obtained by measuring the average thermalexpansion coefficients in the temperature range between 40° and 800° C.using square rod test pieces measuring 3×3×40 mm and having the samecompositions as those of the corresponding evaluation samples and werefired when the above-mentioned evaluation samples were fired.

Table 2 indicates the results of the measurements.

                                      TABLE 2                                     __________________________________________________________________________                                                   Dielectric layer               Insulating layer                               for temperature                               Firing                                                                             Thermal expan-             compensation                   Composition    tempera-                                                                           sion coefficient           Dielectric                     (weight %)     ture 40˜800° C.    material                       Sample No.                                                                          MgO                                                                              SiO.sub.2                                                                        CaO                                                                              (°C.)                                                                       (1/°C. × 10.sup.-6)                                                      Crystal phase      (main component)               __________________________________________________________________________    *1    62 28 10 1420 12.4    Mg.sub.2 SiO.sub.4,MgO                                                                           CaTiO.sub.3                    *2    62 28 10 1420 12.4    Mg.sub.2 SiO.sub.4,MgO                                                                           Mg.sub.2 TiO.sub.4             *3    62 38  0 1400 11.8    Mg.sub.2 SiO.sub.4,MgO                                                                           CaTiO.sub.3                    *4    60 38  0 1400 11.8    Mg.sub.2 SiO.sub.4,MgO                                                                           Mg.sub.2 TiO.sub.4              5    60 30 10 1340 11.6    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7            CaTiO.sub.3                     6    60 30 10 1340 11.6    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7            Mg.sub.2 TiO.sub.4              7    60 40  0 1320 11.7    Mg.sub.2 SiO.sub.4 CaTiO.sub.3                     8    60 40  0 1320 11.7    Mg.sub.2 TiO.sub.4 Mg.sub.2 TiO.sub.4              9    55 35 10 1280 11.6    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7            CaTiO.sub.3                    10    55 35 10 1280 11.6    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7            Mg.sub.2 TiO.sub.4             11    55 35 10 1280 11.6    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7            La.sub.2 Ti.sub.2 O.sub.7      12    55 35 10 1280 11.6    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7            SrTiO.sub.3                    13    55 35 10 1280 11.6    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7            Nd.sub.2 Ti.sub.2 O.sub.7      14    55 40  5 1280 11.6    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7            CaTiO.sub.3                    15    55 40  5 1300 11.6    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7            Mg.sub.2 TiO.sub.4             16    55 40  5 1260 11.6    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7            La.sub.2 Ti.sub.2 O.sub.7      17    55 40  5 1280 11.6    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7            SrTiO.sub.3                    18    55 40  5 1260 10.6    Mg.sub.2 SiO.sub.4,Ca.sub.2 MgSi.sub.2                                        O.sub.7            Nd.sub.2 Ti.sub.2 O.sub.7      *19   52 28 20 1420 11.8    Mg.sub.2 SiO.sub.4,MgO                                                                           La.sub.2 Ti.sub.2 O.sub.7      20    45 35 20 1280 11.9    Mg.sub.2 SiO.sub.4,CaOMgOSiO.sub.4, Ca.sub.2                                  MgSi.sub.2 O.sub.7 CaTiO.sub.3                    21    45 35 20 1280 11.9    Mg.sub.2 SiO.sub.4,CaOMgOSiO.sub.4, Ca.sub.2                                  MgSi.sub.2 O.sub.7 Mg.sub.2 TiO.sub.4             22    45 35 20 1280 11.9    Mg.sub.2 SiO.sub.4,CaOMgOSiO.sub.4, Ca.sub.2                                  MgSi.sub.2 O.sub.7 La.sub.2 Ti.sub.2 O.sub.7      23    45 35 20 1280 11.9    Mg.sub.2 SiO.sub.4,CaOMgOSiO.sub.4, Ca.sub.2                                  MgSi.sub.2 O.sub.7 SrTiO.sub.3                    24    45 35 20 1280 11.9    Mg.sub.2 SiO.sub.4,CaOMgOSiO.sub.4, Ca.sub.2                                  MgSi.sub.2 O.sub.7 Nd.sub.2 Ti.sub.2 O.sub.7      25    45 50  5 1300 11.5    Mg.sub.2 SiO.sub.4,MgSiO.sub.3,                                                                  CaTiO.sub.3.4                  26    45 50  5 1300 11.5    Mg.sub.2 SiO.sub.4,MgSiO.sub.3,                                                                  Mg.sub.2 TiO.sub.4             27    45 50  5 1300 11.5    Mg.sub.2 SiO.sub.4,MgSiO.sub.3,                                                                  La.sub.2 Ti.sub.2 O.sub.7      28    45 50  5 1300 11.5    Mg.sub.2 SiO.sub.4,MgSiO.sub.3,                                                                  SrTiO.sub.3.4                  29    45 50  5 1300 11.5    Mg.sub.2 SiO.sub.4,MgSiO.sub.3,                                                                  Nd.sub.2 Ti.sub.2 O.sub.7      *30   40 28 32 1400 11.7    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4                                              MgO,CaSiO.sub.3    CaTiO.sub.3                    *31   40 28 32 1400 11.7    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4                                              MgO,CaSiO.sub.3    Mg.sub.2 TiO.sub.4             32    40 30 30 1300 11.5    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4                                                                 CaTiO.sub.3                    33    40 30 30 1280 11.5    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4                                                                 Mg.sub.2 TiO.sub.4             34    40 50 10 1260 11.2    Mg.sub.2 SiO.sub.4,MgSiO.sub.3, Ca.sub.2                                      MgSi.sub.2 O.sub.7 CaTiO.sub.3                    35    40 50 10 1280 11.2    Mg.sub.2 SiO.sub.4,MgSiO.sub.3, Ca.sub.2                                      MgSi.sub.2 O.sub.7 Mg.sub.2 TiO.sub.4             36    40 50 10 1240 11.2    Mg.sub.2 SiO.sub.4,MgSiO.sub.3, Ca.sub.2                                      MgSi.sub.2 O.sub.7 La.sub.2 TiO.sub.4             37    40 50 10 1280 11.2    Mg.sub.2 SiO.sub.4,MgSiO.sub.3, Ca.sub.2                                      MgSi.sub.2 O.sub.7 SrTiO.sub.3                    38    40 50 10 1240 11.2    Mg.sub. 2 SiO.sub.4,MgSiO.sub.3, Ca.sub.2                                     MgSi.sub.2 O.sub.7 Nd.sub.2 Ti.sub.2 O.sub.7      39    40 60  0 1320 11.5    Mg.sub.2 SiO.sub.4 CaTiO.sub.3                    40    40 60  0 1320 11.5    Mg.sub.2 SiO.sub.4 Mg.sub.2 TiO.sub.4             41    38 40 22 1240 11.8    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7 CaTiO.sub.3                    42    38 40 22 1280 11.8    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7 Mg.sub.2 TiO.sub.4             43    38 40 22 1260 11.8    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7 La.sub.2 Ti.sub.2 O.sub.7      44    38 40 22 1280 11.8    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7 SrTiO.sub.3                    45    38 40 22 1240 11.8    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7 Nd.sub.2 Ti.sub.2 O.sub.7      46    38 52 10 1260 11.2    Mg.sub.2 SiO.sub.4,MgSiO.sub.3, Ca.sub.2                                      MgSi.sub.2 O.sub.7 CaTiO.sub.3                    47    38 52 10 1260 11.2    Mg.sub.2 SiO.sub.4,MgSiO.sub.3, Ca.sub.2                                      MgSi.sub.2 O.sub. 7                                                                              Mg.sub.2 TiO.sub.4             48    38 52 10 1260 11.2    Mg.sub.2 SiO.sub.4,MgSiO.sub.3, Ca.sub.2                                      MgSi.sub.2 O.sub.7 La.sub.2 Ti.sub.2 O.sub.7      49    38 52 10 1260 11.2    Mg.sub.2 SiO.sub.4,MgSiO.sub.3, Ca.sub.2                                      MgSi.sub.2 O.sub.7 SrTiO.sub.3                    50    38 52 10 1260 11.2    Mg.sub.2 SiO.sub.4,MgSiO.sub.3, Ca.sub.2                                      MgSi.sub.2 O.sub.7 Nd.sub.2 Ti.sub.2 O.sub.7      *51   38 62  0 1280 10.0    MgSiO.sub.3        CaTiO.sub.3                    *52   30 62  0 1280 10.0    MgSiO.sub.3        Mg.sub.2 TiO.sub.4             53    30 40 30 1340 11.4    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7 CaTiO.sub.3                    54    30 40 30 1340 11.4    Mg.sub.2 SiO.sub.4,CaMgSiO.sub.4, Ca.sub.2                                    MgSi.sub.2 O.sub.7 Mg.sub.2 TiO.sub.4             55    30 60 10 1320 10.4    MgSiO.sub.3, Mg.sub.2 SiO.sub.4                                                                  CaTiO.sub.3                    56    30 60 10 1320 10.4    MgSiO.sub.3, Mg.sub.2 SiO.sub.4                                                                  Mg.sub.2 TiO.sub.4             *57   28 40 32 1360 11.3    Mg.sub.2 SiO.sub.4,Ca.sub.2 SiO.sub.4,                                        Ca.sub.2 MgSi.sub.2 O.sub.7                                                                      CaTiO.sub.3                    *58   28 40 32 1360 11.3    Mg.sub.2 SiO.sub.4,Ca.sub.2 SiO.sub.4,                                        Ca.sub.2 MgSi.sub.2 O.sub.7                                                                      Mg.sub.2 TiO.sub.4             *59   28 50 22 1300  9.8    Mg.sub.2 SiO.sub.4,CaMgSi.sub.2 O.sub.6                                                          CaTiO.sub.3                    *60   28 50 22 1300  9.8    Mg.sub.2 SiO.sub.4,CaMgSi.sub.2 O.sub.6                                                          Mg.sub.2 TiO.sub.4             *61   28 62 10 1350  9.5    MgSiO.sub.3,CaMgSi.sub.2 O.sub.6                                                                 CaTiO.sub.3                    *62   28 62 10 1350  9.5    MgSiO.sub.3,CaMgSi.sub.2 O.sub.6                                                                 Mg.sub.2 TiO.sub.4             __________________________________________________________________________                           Dielectric layer                                                              for temperature                                                               compensation                                                                          Capacitor section                                                     Thermal expan-                                                                        Temperature  Dieletric                                                sion coefficient                                                                      coefficient                                                                          Insulation                                                                          breakdown                                                40˜800° C.                                                               TCC    resistance                                                                          voltage                                            Sample No.                                                                          (1/°C. × 10.sup.-6)                                                      (ppm/°C.)                                                                     (Ω)                                                                           (V)   Remarks                     __________________________________________________________________________                     *1    11.5    --     --    --    Nonmea-                                                                       surable                                      *2    10.5    --     --    --    Nonmea-                                                                       surable                                      *3    11.5    --     --    --    Nonmea-                                                                       surable                                      *4    10.5    --     --    --    Nonmea-                                                                       surable                                       5    11.5    N740   >10.sup.12                                                                          >1500 FIG. 3, G                                     6    10.5    N3     >10.sup.12                                                                          >1500  "                                            7    11.5    N755   >10.sup.12                                                                          >1500 FIG. 3, A                                     8    10.5    N3     >10.sup.12                                                                          >1500  "                                            9    11.5    N750   >10.sup.12                                                                          >1500                                              10    10.5    N4     >10.sup.12                                                                          >1500                                              11    11.0    N4     >10.sup.12                                                                          >1500                                              12    11.0    N2200  >10.sup.12                                                                          >1500                                              13    10.7    P4     >10.sup.12                                                                          >1500                                              14    11.5    N750   >10.sup.12                                                                          >1500                                              15    10.5    N6     >10.sup.12                                                                          >1500                                              16    11.0    N4     >10.sup.12                                                                          >1500                                              17    11.0    N2100  >10.sup.12                                                                          >1500                                              18    10.7    P6     >10.sup.12                                                                          >1500                                              *19   11.0    --     --    --    Nonmea-                                                                       surable                                      20    11.5    N740   >10.sup.12                                                                          >1500                                              21    10.5    N7     >10.sup.12                                                                          >1500                                              22    11.0    N5     >10.sup.12                                                                          >1500                                              23    11.0    N2300  >10.sup.12                                                                          >1500                                              24    10.7    P2     >10.sup. 12                                                                         >1500                                              25    11.5    N770   >10.sup.12                                                                          >1500                                              26    10.5    N7     >10.sup.12                                                                          >1500                                              27    11.0    N7     >10.sup.12                                                                          >1500                                              28    11.0    N2200  >10.sup.12                                                                          >1500                                              29    10.7    P2     >10.sup.12                                                                          >1500                                              *30   11.5    --     --    --    Nonmea-                                                                       surable                                      *31   10.5    --     --    --    Nonmea-                                                                       surable                                      32    11.5    N760   >10.sup.12                                                                          >1500 FIG. 3, F                                    33    10.5    N6     >10.sup.12                                                                          >1500 FIG. 3, F                                    34    11.5    N742   >10.sup.12                                                                          >1500                                              35    10.5    N3     >10.sup.12                                                                          >1500                                              36    11.0    P4     >10.sup.12                                                                          >1500                                              37    11.0    N2100  >10.sup.12                                                                          >1500                                              38    10.7    P8     >10.sup.12                                                                          >1500                                              39    11.5    N753   >10.sup.12                                                                          >1500 FIG. 3, B                                    40    10.5    N6     >10.sup.12                                                                          >1500 FIG. 3, B                                    41    11.5    N766   >10.sup.12                                                                          >1500                                              42    10.5    N8     >10.sup.12                                                                          >1500                                              43    11.0    P1     >10.sup.12                                                                          >1500                                              44    11.0    N2200  >10.sup.12                                                                          >1500                                              45    10.7    P5     >10.sup.12                                                                          >1500                                              46    11.5    N740   >10.sup.12                                                                          >1500                                              47    10.5    N5     >10.sup.12                                                                          >1500                                              48    11.0    P2     >10.sup.12                                                                          >1500                                              49    11.0    N2300  >10.sup.12                                                                          >1500                                              50    10.7    P3     >10.sup.12                                                                          >1500                                              *51   11.5    N753    10.sup.10                                                                            540                                              *52   10.5    N2      10.sup.10                                                                            600                                              53    11.5    N746   >10.sup.12                                                                          >1500 FIG. 3, E1                                   54    10.5    N4     >10.sup.12                                                                          >1500 FIG. 3, E1                                   55    11.5    N740   >10.sup.12                                                                          >1500 FIG. 3, C                                    56    10.5    N3     >10.sup.12                                                                          >1500 FIG. 3, C                                    *57   11.5    N900    10.sup.11                                                                            800                                              *58   10.5    N3      10.sup.10                                                                           1000                                              *59   11.5    N870    10.sup.8                                                                             200                                              *60   10.5    N1      10.sup.9                                                                             300                                              *61   11.5    N920    10.sup.7                                                                             100                                              *62   10.5    N2      10.sup.8                                                                             300                             __________________________________________________________________________     Samples indentified by the numbers marked * are excluded from the scope o     the claims of the second invention.                                      

With the multilayer substrate with inner capacitors of the secondinvention, the insulating layer mainly comprising magnesia and silica ormagnesia, silica and calcia being superior in high-frequency insulationperformance can be co-fired with the dielectric material for temperaturecompensation. In addition, the thermal expansion coefficient of theinsulating layer can be set very close to that of the dielectric layer.The substrate can thus include the capacitor section for temperaturecompensation, which is high in the insulation resistance and dielectricbreakdown voltage without causing cracks in the dielectric layer. As aresult, the invention can offer a multilayer substrate with innercapacitors that is miniaturized and high in density, ideally suited forhybrid substrates for example.

The object of the third invention is to provide a multilayer substratewith inner capacitors including two different types of capacitorsections: a type with high electrostatic capacitance and a type withstable temperature characteristics, wherein insulating layers mainlycomprising MgO, SiO₂ and CaO and superior in high-frequency insulatingperformance can be co-fired with a dielectric material mainly comprisingbarium titanate (BaTiO₃) and having a high dielectric constant, and adielectric material mainly comprising dielectric ceramics fortemperature compensation.

The insulating layers of the multilayer substrate with inner capacitorsof the third invention, between which capacitor sections mainly composedof a dielectric material mainly comprising barium titanate (BaTiO₃) anddielectric ceramics for temperature compensation are sandwiched, areinsulating layers mainly comprising magnesia (MgO), silica (SiO₂) andcalcia (CaO) within the area surrounded by the lines connecting pointsA, B₁. D, E₁, F and G shown in FIG. 4. The insulating layer includes atleast one crystal phase of forsterite (Mg₂ SiO₄), merwinite (Ca₃ MgSi₂O₈), monticellite (CaMgSiO₄), akermanite (Ca₂ MgSi₂ O₇) or enstatite(MgSiO₃). The dielectric layers and the insulating layers, between whichthe capacitor sections being composed of the dielectric layer portionsand electrode layers are sandwiched, can be co-fired. X, Y and Zrespectively represent the weight percent values of magnesia (MgO),silica (SiO₂) and calcia (CaO).

    ______________________________________                                                X           Y     Z                                                   ______________________________________                                        A         60            36     4                                              .sub. B.sub.1                                                                           46            50     4                                              D         30            50    20                                              .sub. E.sub.1                                                                           30            40    30                                              F         40            30    30                                              G         60            30    10                                              ______________________________________                                    

In the composition of the above-mentioned insulating layer shown in FIG.4, if the content of MgO exceeds 60 weight %, the firing temperaturebecomes 1360° C. or more. This prevents the insulating layer from beingco-fired with the two different dielectric materials, and periclase(MgO) deposits as a crystal phase, thereby reducing resistance againsthumidity. If the content of MgO is less than 30 weight %, the insulationresistance value and dielectric breakdown voltage reduce beyond theirpractical ranges.

If the content of SiO₂ exceeds 50 weight %, the thermal expansioncoefficient of the insulating layer reduces. Due to the difference inthermal expansion coefficient between the insulating layer and thedielectric layers, cracks are caused in the dielectric layers and thepredetermined dielectric characteristics cannot be obtained. If thecontent of SiO₂ is less than 30 weight %, the firing temperature becomes1360° C. or more. This prevents the insulating layer from being co-firedwith the two different dielectric layers.

If the content of CaO exceeds 30 weight %, the firing temperaturebecomes 1400° C. or more. This prevents the insulating layer from beingco-fired with the two different dielectric layers. Calcium silicate,such as CaSiO₃ or Ca₂ SiO₄ deposits, thereby reducing the insulationresistance value and dielectric breakdown voltage beyond their practicalranges. If the content of CaO is less than 4 weight %, the reactivity ofCaO with the ceramics mainly comprising barium titanate (BaTiO₃) issignificantly high. This prevents generation of capacitor sectionshaving high electrostatic capacitance.

Therefore, the composition of the above-mentioned insulating layer isrestricted within the area surrounded by the lines connecting points A,B₁, D, E₁, F and G as shown in FIG. 4.

By making adjustment so that the main components, magnesia (MgO), silica(SiO₂) and calcia (CaO) of the insulating layers, between which thecapacitor section are sandwiched, are within the area surrounded by thelines connecting points A, B₁, D, E₁, F and G as shown in FIG. 4, theinsulating layer can be co-fired with the dielectric layer mainlycomprising barium titanate (BaTiO₃) and the dielectric ceramics fortemperature compensation at 1240° to 1340° C. (the firing temperaturerange of the dielectric layers). In addition to the crystal phase offorsterite (Mg₂ SiO₄), at least one crystal phase of merwinite (Ca₃MgSi₂ O₈), monticellite (CaMgSiO₄), akermanite (Ca₂ MgSi₂ O₇) orenstatite (MgSiO₃) is formed in the fired insulating layer. The thermalexpansion coefficients of the four crystal phases differ from that ofthe crystal phase of forsterite. The thermal expansion coefficient ofthe insulating layer can thus be adjusted. Therefore, thermal stressgeneration is minimal after the co-firing of the layers.

EXAMPLE 3

The multilayer substrate with inner capacitors of the third invention isdetailed below taking an example shown in FIG. 7.

FIG. 7 is a cross section of an example of a multilayer substrate withinner capacitors of the third invention.

Referring to FIG. 7, numeral 1 represents an insulating layer, numerals2 and 2' represent capacitor sections, numeral 3 represents an electricwiring conductor. The capacitor section 2 is composed of dielectriclayer portions 4 mainly comprising barium titanate (BaTiO₃) andelectrode layers 5 laminated alternately. In the same way, the capacitorsection 2' is composed of dielectric layer portions 4' mainly comprisinga dielectric ceramics for temperature compensation and electrode layers5' laminated alternately.

    ______________________________________                                                X            Y     Z                                                  ______________________________________                                        .sub. A.sub.1                                                                           60             36     4                                             .sub. B.sub.1                                                                           46             50     4                                             D         30             50    20                                             .sub. E.sub.1                                                                           30             40    30                                             F         40             30    30                                             G         60             30    10                                             ______________________________________                                    

X, Y and Z respectively represent weight percent values of magnesia(MgO), silica (SiO₂) and calcia (CaO).

The insulating layer 1 is made by mixing ceramic material powdercomprising MgO and SiO₂ an CaO so that its composition is within thearea surrounded by the lines connecting points A₁, B₁, D, E₁, F and G asshown in FIG. 4 and by calcining the mixture at 1000° to 1300° C. Thecalcined substance is pulverized into ceramic powder and mixed withappropriate organic binders, dispersing agents, plasticizers andsolvents to process slurry. The slurry is processed into green sheets bya known method such as the doctor blade method. A plurality of the greensheets are laminated to form the insulating layer 1.

The capacitor sections 2 and 2' are made as follows: the dielectricmaterial mainly comprising BaTiO₃ and the dielectric material mainlycomprising a dielectric ceramics for temperature compensation arerespectively mixed and adjusted with organic binders and solvents toform slurry two different types of slurry. Each type of slurry isprocessed into green sheets by a known method such as the slip castmethod. On the obtained dielectric green sheet, silver-palladium (Ag-Pd)alloy paste is printed by the screen printing method according to thepredetermined electrode patterns to form the electrode layers 5 and 5'.

To obtain continuity between the top and bottom surfaces of theinsulating layer 1 and capacitor sections 2 and 2', through-holesections 6 are formed by punching the green sheets of the insulating anddielectric layers. In the through-hole sections 6, the above-mentionedalloy paste is filled.

The above-mentioned green sheets of the insulating layer, the dielectriclayers mainly comprising barium titanate (BaTiO₃) and the dielectriclayer comprising dielectric ceramics for temperature compensationrespectively are laminated and pressed at heating. The obtainedlaminations are subjected to a binder burnout process at 200° to 400°C., then co-fired at 1240° to 1340° C. As a result, a multilayersubstrate with the capacitor sections 2 and 2' is obtained.

The capacitor sections 2 and 2' are formed by laminating the twodifferent dielectric layers 4' mainly comprising dielectric ceramics fortemperature compensation on the top and bottom surfaces of thedielectric layer 4 mainly comprising barium titanate (BaTiO₃) with ahigh dielectric constant. When the layers are co-fired, the laminationcan prevent Ti and Ba (with high diffusion speed) from moving in thedielectric layers. This prevents the temperature characteristics of thecapacitor sections from being deteriorated.

By printing, Ag-Pd electric wiring conductor patterns are formed on theinsulating layer 1 that was co-fired. Resistor patterns comprisingruthenium oxide (RuO₂) are also formed on the insulating layer 1 byprinting. The obtained substance is then fired at about 850° C. in theair to obtain a multilayer substrate with inner capacitors and resistors7.

When forming the electric wiring conductor patterns using a materialmainly comprising copper (Cu), a resistor material mainly comprisinglanthanum boride (LaB₆) and stannic (SnO₂) is used to form resistorpatterns. The resistor patterns are then fired at about 900° C. in anatmosphere of nitrogen. As a result, a multilayer substrate with innercapacitors is obtained in the same way as described above.

The various characteristics of the capacitor sections are notdeteriorated if the total amount of unavoidable impurities remaining inthe insulating layer 1, alumina (Al₂ O₃), ferric oxide (Fe₂ O₃) andbarium oxide (BaO), does not exceed 5 weight % of the total (100 weight%) of MgO, SiO₂ and CaO.

The third invention is detailed further taking an example of the thirdinvention and a contrast example.

Various types of ceramic material powder comprising MgO and SiO₂ and CaOare mixed so that the composition of the insulating layer has the ratiosindicated in Table 3 and calcined at 1100° to 1300° C. The calcinedsubstance is pulverized to obtain the desired particle size. Appropriateorganic binders and solvents are then added to the obtained materialpowder to form slurry. The slurry is processed by the doctor blademethod to form a green sheet of 200 μm in thickness. The green sheet isthen punched to obtain insulating sheets of 170 mm square.

The material powder mainly comprising barium titanate (BaTiO₃) and thematerial powder mainly comprising the dielectric material fortemperature compensation indicated in Table 4 are respectively mixedwith appropriate binders and solvents to form two different types ofslurry. The two types of slurry are processed by the slip cast method toform green sheets of 20 to 60 μm in thickness so that the capacitancevalues of the two capacitor sections can be set. The sheets are thenpunched and formed to dielectric sheets of 170 mm square.

On the two different types of the dielectric sheets, Ag-Pd alloy pasteis applied by a thick-film printing method such as the screen printingmethod to form electrode patterns of about 1 to 10 mm square dependingon the required electrostatic capacitance.

The through-hole sections formed in the insulating sheets and the twodifferent types of the dielectric sheets are filled with the Ag-Pd alloypaste by the screen printing method.

A plurality of the dielectric sheets comprising dielectric ceramics fortemperature compensation are sandwiched between the top and bottomsurfaces of the laminated dielectric sheets comprising barium titanateand pressed at heating. The obtained laminations are subjected to abinder burnout process at 200° to 400° C. in the air and fired in theair at the temperatures indicated in Table 3.

The evaluation samples made described above were checked forshort-circuit between the electrode layers of the high-capacitancecapacitor section and the temperature compensation capacitor sectionsusing an LCR meter. The electrostatic capacitance of thehigh-capacitance capacitor section was then measured at a frequency of 1kHz and at an input signal level of 1.0 Vrms using the LCR meteraccording to the JIS C 5102 standards. Relative permittivity (ε_(r)) wascalculated from the electrostatic capacitance. The electrostaticcapacitance of the temperature compensation capacitor section was alsomeasured at -55° C. to 125° C. and the change ratios of theelectrostatic capacitance values are calculated as temperaturecoefficients (TCC). In addition, the insulation resistance values of thecapacitor sections were measured 60 seconds after 25 V DC was applied tothe capacitor sections. The dielectric breakdown voltage values weremeasured across the terminals of each capacitor section when voltage wasapplied at a boosting speed of 100 V/second and in an moment the leakcurrent value exceeded 1.0 mA.

The evaluation samples were used for X-ray diffraction of the crystalphase of the insulating layer. The crystal phase was identifiedaccording to the X-ray diffraction pattern on the surface of eachevaluation sample. The thermal expansion coefficients of the insulatingand dielectric layers were obtained by measuring the average thermalexpansion coefficients in the temperature range between 40° and 800° C.using square rod test pieces measuring 3×3×40 mm and having the samecompositions as those of the corresponding evaluation samples and firedwhen the above-mentioned evaluation samples were fired.

Tables 3 and 4 indicate the results of the measurement.

                                      TABLE 3                                     __________________________________________________________________________    Insulating layer                                                                             Firing                                                                             Thermal expan-                                            Composition    tempera-                                                                           sion coefficient                                          (weight %)     ture 40˜800° C.                                   Sample No.                                                                          MgO                                                                              SiO.sub.2                                                                        CaO                                                                              (°C.)                                                                       (1/°C. × 10.sup.-6)                                                      Crystal phase          Remarks                    __________________________________________________________________________    * 1, 2.sup.                                                                         62 28 10 1360 12.2    Mg.sub.2 SiO.sub.4, MgO                           * 3, 4.sup.                                                                         62 36  2 1400 12.1    Mg.sub.2 SiO.sub.4, MgO                           5, 6  60 30 10 1320 11.9    Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4                                                                    FIG. 4,G                   7, 8  60 36  4 1340 11.8    Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4                                                                    FIG. 4,A                    9˜15                                                                         56 40  4 1240 11.6    Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7                                16˜22                                                                         54 36 10 1260 11.7    Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7                                * 23, 24.sup.                                                                       52 28 20 1400 12.1    Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4 , MgO           25˜31                                                                         46 40 14 1280 11.7    Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7                                32, 33                                                                              46 50  4 1280 11.3    Mg.sub.2 SiO.sub.4, Ca.sub.2 MgSi.sub.2                                       O.sub.7, MgSiO.sub.3    FIG. 4,B1                 * 34, 35.sup.                                                                       46 52  2 1300 10.8    Mg.sub.2 SiO.sub.4, MgSiO.sub.3                   36˜42                                                                         44 36 20 1260 11.8    Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7                                * 43, 44.sup.                                                                       40 28 32 1360 11.7    Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7, MgO                           45, 46                                                                              40 30 30 1280 11.8    Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7     FIG. 4,F                   47˜53                                                                         40 40 20 1260 11.8    Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7                                54˜60                                                                         40 50 10 1240 11.5    Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4,                                            MgSiO.sub.3                                       61, 62                                                                              35 35 30 1340 11.7    Mg.sub.2 SiO.sub.4, Ca.sub.3 MgSi.sub.2                                       O.sub.8, CaMgSiO.sub.4                            63˜ 69                                                                        35 45 20 1280 11.5    Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7                                70, 71                                                                              30 40 30 1280 11.6    Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7, Ca.sub.3 MgSi.sub.2                                       O.sub.8                 FIG. 4,E1                 72, 73                                                                              30 50 20 1240 11.4    Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4                                                                    FIG. 4,Db.3                * 74, 75.sup.                                                                       28 40 32 1280 11.7    Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4 Ca.sub.2                                    SiO.sub.4                                         * 76, 77.sup.                                                                       28 52 20 1220 10.8    Mg.sub.2 SiO.sub.4, Ca.sub.2 MgSi.sub.2                                       O.sub.7, Ca.sub.2 MgSi.sub.2 O.sub.6              __________________________________________________________________________     Samples identified by the numbers marked * are excluded from the scope of     the claims of the third invention.                                       

    TABLE 4       High-capacitance capacitor section Temperature-compensation capacitor     section    Thermal expansion coeffi-   Dielectric  Thermal expansion     coeffi- Temperature  Dielectric   Dielectric cient of dielectric layer     Relative Insulation breakdown Dielectric cient of dielectric layer     coefficient Insulation breakdown  material 40˜800° C.     permittivity resistance voltage material 40˜800° C. TCC     resistance voltage Sample No. (main component) (1/°C. ×     10.sup.-6) ε      Γ (Ω) (V) (main component) (1/°C. × 10.sup.-6)     (ppm/°C.) (Ω) (V) Remarks       * 1.sup.       BaTiO.sub.3 12.4 -- -- -- CaTiO.sub.3 12.0 -- -- -- Nonmeasurable *     2.sup.  " " -- -- -- Mg.sub.2 TiO.sub.4 10.5 -- -- -- Nonmeasurable *     3.sup.  " " -- -- -- CaTiO.sub.3 12.0 -- -- -- Nonmeasurable * 4.sup.  "     " -- -- -- Mg.sub.2 TiO.sub.4 10.5 -- -- -- Nonmeasurable  5 " " 2500     >10.sup.10 >500 CaTiO.sub.3 12.0  N780 >10.sup.12   >1500  6 " " " " "     Mg.sub.2 TiO.sub.4 10.5 N3 " "  7 " " " " " CaTiO.sub.3 12.0  N750 " "     8 " " " " " Mg.sub.2 TiO.sub.4 11.0 N3 " "  9 " " " " " BaTi.sub.4     O.sub.7 10.5 P2 " " 10 " " " " " CaTiO.sub.3 12.0  N750 " " 11 " " " " "     Mg.sub.2 TiO.sub.4 10.5 N4 " " 12 " " " " " Mg.sub.2 TiO.sub.4 11.0     N720 " " 13 " " " " " La.sub.2 Ti.sub.2 O.sub.7 10.6 N4 " " 14 " " " " "     SrTiO.sub.3 11.6   N2200 " " 15 " " " " " Nd.sub.2 Ti.sub.2 O.sub.7 10.7     P6 " " 16 " " " " " BaTi.sub.4      O.sub.9 10.5 P3 " " 17 " " " " " CaTiO.sub.3 12.0  N760 " " 18 " " " "     " Mg.sub.2 TiO.sub.4 10.5 N3 " " 19 " " " " " Mg.sub.2 TiO.sub.4 11.0     N720 " " 20 " " " " " La.sub.2 Ti.sub.2 O.sub.7 10.6 N2 " " 21 " " " " "     SrTiO.sub.3 11.0   N2300 " " 22 " " "  " " Nd.sub.2 Ti.sub.2 O.sub.9     10.7 P3 " " * 23.sup.       " " -- -- -- CaTiO.sub.3 12.0 -- -- -- Nonmeasurable * 24.sup.    " "     -- -- -- Mg.sub.2 TiO.sub.4 10.5 -- -- -- Nonmeasurable 25 " " 2500     >10.sup.10 >500 BaTi.sub.4 O.sub.9 10.5 P8 >10.sup.12   >1500 26 " " " "     " CaTiO.sub.3 12.0  N750 " " 27 " " " " " Mg.sub.2 TiO.sub.4 10.5 N2 " "     28 " " " " " Mg.sub.2 TiO.sub.4 11.0  N730 " " 29 " " " " " La.sub.2     Ti.sub.2 O.sub.7 10.6 N4 " " 30 " " " " " SrTiO.sub.3 11.0   N2100 " "     31 " " " " " Nd.sub.2 Ti.sub.2      O.sub.7 10.7 P3 " " 32 " " " " " CaTiO.sub.3 12.0  N750 " " 33 " " " "     " Mg.sub.2 TiO.sub.4 10.5 N6 " " * 34.sup.    " " 1950 .sup.  10.sup.7     80 CaTiO.sub.3 12.0  N755 10.sup.10  1000 * 35.sup.    " " 2100 .sup.     10.sup.8  150 Mg.sub.2 TiO.sub.4 10.5 N3 10.sup.10   500 36 " " 2500     >10.sup.10 >500 BaTi.sub.4 O.sub.9 10.5  P10 >10.sup.12   >1500 37 " " "     " " CaTiO.sub.3 12.0  N750 " " 38 " " " " " Mg.sub.2 TiO.sub.4 10.5 N5 "     " 39 " " " " " Mg.sub.2 TiO.sub.4 11.0  N710 " " 40 " " " " " La.sub.2     Ti.sub.2 O.sub.7 10.6 N7 " " 41 " " " " " SrTiO.sub.3 11.0   N2100 " "     42 " " " " " Nd.sub.2 Ti.sub.2 O.sub.7 10.7 P5 " " * 43.sup.    " " 1800     .sup.  10.sup.7  300 CaTiO.sub.3 12.0  N900 10.sup.11  1200 * 44.sup.     " " 2100 .sup.  10.sup.8 250 Mg.sub.2 TiO.sub.4 10.5 N2 "  1000 45 " "     2500 >10.sup.10 >500 CaTiO.sub.3 O.sub.9 12.0  N740 >10.sup.12   >1500     46 " " " " " Mg.sub.2 TiO.sub.4 10.5 N1 " " 47 " " " " " BaTi.sub.4     O.sub.9 10.5 P8 "  " 48 " " " " " CaTiO.sub.3 12.0  N760 " " 49 " " " "     " Mg.sub.2 TiO.sub.4 10.5 N3 " " 50 " " " " " Mg.sub.2 TiO.sub.4 11.0     N750 " " 51 " " " " " La.sub.2 Ti.sub.2 O.sub.9 10.6 P4 " " 52 " " " " "     SrTiO.sub.3 11.0   N2200 " " 53 " " " " " Nd.sub.2 Ti.sub.2 O 10.7 P3 "     " 54 " " " " " BaTi.sub.4 O.sub.9 10.5  P15 " " 55 " " " " " CaTiO.sub.3     12.0  N750 " " 56 " " " " " Mg.sub.2 TiO.sub.4 10.5 N2 " " 57 " " " " "     Mg.sub.2 TiO.sub.4 11.0  N720 " " 58 " " " " " La.sub.2 Ti.sub.2 O.sub.9     10.6 P3 " " 59 " " " " " SrTiO.sub.3 11.0   N2100 " " 60 " " " " "     Nd.sub.2 Ti.sub.2 O 10.7 P5 " " 61 " " " " " CaTiO.sub.3 12.0  N760 " "     62 " " " " " Mg.sub.2 TiO.sub.4 10.5 N3 " " 63 " " " " " BaTiO.sub.4     O.sub.9 10.5  P10 " " 64 " " " " " CaTiO.sub.3 12.0  N746 " " 65 " " " "     " Mg.sub.2 TiO.sub.4 10.5 N4 " " 66 " " " " " Mg.sub.2 TiO.sub.4 11.0     N720 " " 67 " " " " " La.sub.2 Ti.sub.2 O.sub.9 10.6 P2 " " 68 " " " " "     SrTiO.sub.3 11.0   N2200 " " 69 " " " " " Nd.sub.2 Ti.sub.2 O.sub.7 10.7     P4 " " 70 " " " " " CaTiO.sub.3 12.0  N745 " " 71 " " " " " Mg.sub.2     TiO.sub.4 10.5 N7 " " 72 " " " " " CaTiO.sub.3 12.0  N760 " " 73 " " " "     " Mg.sub.2 TiO.sub.4 10.5  N10 " " * 74.sup.    " " 2300 .sup.  10.sup.9     " CaTiO.sub.3 12.5   N1230 "  1200 * 75.sup.    " " 2300 .sup.     10.sup.9  400 Mg.sub.2 TiO.sub.4 10.5  N50 10.sup.11  1000 * 76.sup.     " " 1800 .sup.  10.sup.8  100 CaTiO.sub.3 10.2   N1100 10.sup.10   800 *     77.sup.    " " 1800 .sup.  10.sup.7  150 Mg.sub.2 TiO.sub.4 10.0  N60     10.sup.11     Samples identified by the numbers marked * are excluded from the scope of     the claims of the third invention.

With the multilayer substrate with inner capacitors of the thirdinvention, the insulating layer mainly comprising magnesia, silica andcalcia being superior in high-frequency insulation performance can beco-fired with the dielectric layer comprising barium titanate (BaTiO₃)with a high dielectric constant and the dielectric layer mainlycomprising various dielectric ceramics for temperature compensationwithout causing reaction between the two different dielectric layers. Inaddition, the thermal expansion coefficient of the insulating layer canbe set very close to those of the dielectric layers. The substrate canthus include both the capacitor section with high electrostaticcapacitance and the temperature compensation capacitor section withsuperior temperature characteristics, both of which are superior in theinsulation resistance and dielectric breakdown voltage, without causingcracks in the dielectric layer. As a result, the invention can offer amultilayer substrate with inner capacitors that is miniaturized and highin density, ideally suited for hybrid substrates.

The insulating layers of the multilayer substrate with inner capacitorsof the fourth invention, between which capacitor sections mainlycomposed of a dielectric ceramics mainly comprising barium titanate(BaTiO₃) and dielectric ceramics for temperature compensation aresandwiched, are insulating layers mainly comprising magnesia (MgO),silica (SiO₂) and calcia (CaO) within the area surrounded by the linesconnecting points A₁, B₂, C, E₁, F and G shown by weight percent in FIG.5. The content of alumina (Al₂ O₃) in the insulating layer is between 1and 15 weight % of the total (100 weight %) of the magnesia (MgO),silica (SiO₂) and calcia (CaO). The insulating layer includes at leastone crystal phase of forsterite (Mg₂ SiO₄), merwinite (Ca₃ MgSi₂ O₈),monticellite (CaMgSiO₄), akermanite (Ca₂ MgSi₂ O₄), enstatite (MgSiO₃)or spinel (MgAl₂ O₄). The dielectric layers and the insulating layers,between which the capacitor sections being composed of the dielectriclayer portions and electrode layers are sandwiched, can be co-fired.Points A₁, B₂, C, E₁, F and G and the lines connecting the points areexcluded from the composition area of the insulating layer.

    ______________________________________                                               MgO         SiO.sub.2                                                                            CaO                                                 ______________________________________                                        .sub. A.sub.1                                                                          60            36      4                                              .sub. B.sub.2                                                                          36            60      4                                              C        30            60     10                                              .sub. E.sub.1                                                                          30            40     30                                              F        40            30     30                                              G        60            30     10                                              ______________________________________                                    

In the composition of the above-mentioned insulating layer, if thecontent of MgO is 60 weight % or more, the firing temperature becomes1300° C. or more and the reactivity between the insulating layer and thetwo different dielectric materials becomes high. This prevents theinsulating layer from being co-fired with the two different dielectricmaterials, and periclase (MgO) deposits as a crystal phase, therebyreducing resistance against humidity. If the content of MgO is 30 weight% or less, the insulation resistance value and dielectric breakdownvoltage reduce beyond their practical ranges.

If the content of SiO₂ is 60 weight % or more, the thermal expansioncoefficient of the insulating layer reduces. Due to the difference inthermal expansion coefficient between the insulating layer and thedielectric layers, cracks are caused in the dielectric layers and thepredetermined dielectric characteristics cannot be obtained. If thecontent of SiO₂ is 30 weight % or less, the firing temperature becomes1300° C. or more. This prevents the insulating layer from being co-firedwith the two different dielectric.

If the content of CaO is 30 weight % or more, the reactivity between theinsulating layer and the two different dielectric materials becomeshigh. This prevents the insulating layer from being co-fired with thetwo different dielectric materials. Calcium silicate, such as CaSiO₃ orCa₂ SiO₄ deposits, thereby reducing the insulation resistance value anddielectric breakdown voltage beyond their practical ranges. If thecontent of CaO is 4 weight % or less, the thermal expansion coefficientof the insulating layer reduces and the dielectric layers are crackeddue to the same reason as described above, preventing the predetermineddielectric characteristics from being obtained.

If the content of Al₂ O₃ exceeds 15 weight %, thermal expansioncoefficient of the insulating layer reduces. If the content of Al₂ O₃ isless than 1 weight %, the firing temperature becomes 1300° C. or more,causing the problem similar to that described above.

Therefore, the composition of the above-mentioned insulating layer isrestricted within the area described above. The more favorable area isthat surrounded by the lines connecting points A₁ ', B₂ ', C', E₁ ', F₁' and G' as shown in FIG. 5. In addition, the content of alumina (Al₂O₃) in the insulating layer is restricted in the range between 2 and 15weight % of the total (100 weight %) of the magnesia (MgO), silica(SiO₂) and calcia (CaO).

    ______________________________________                                               MgO         SiO.sub.2                                                                            CaO                                                 ______________________________________                                        A.sub.1 '                                                                              55            40      5                                              B.sub.2 '                                                                              45            50      5                                              C'.sub.  40            50     10                                              E.sub.1 '                                                                              40            40     20                                              F.sub.1 '                                                                              45            35     20                                              G'.sub.  55            35     10                                              ______________________________________                                    

By making adjustment so that the main components, magnesia (MgO), silica(SiO₂), calcia (CaO) and alumina (Al₂ O₃) of the insulating layers,between which the capacitor sections are sandwiched, are within theabove-mentioned area, the insulating material can be co-fired with thedielectric material mainly comprising barium titanate (BaTiO₃) and thedielectric ceramics for temperature compensation at 1220° to 1280° C.(the firing temperature range of the dielectric materials). In additionto the crystal phase of forsterite (Mg₂ SiO₄), at least one crystalphase of merwinite (Ca₃ MgSi₂ O₈), monticellite (CaMgSiO₄), akermanite(Ca₂ MgSi₂ O₇), enstatite (MgSiO₃) or spinel (MgAl₂ O₄) is formed in thefired insulating layer. The thermal expansion coefficients of the fivecrystal phases differ from that of the crystal phase of forsterite. Thethermal expansion coefficient of the insulating layer can thus beadjusted. Therefore, thermal stress generation is minimal after theco-firing of the layers.

By adding alumina (Al₂ O₃) as a main component of the insulating layer,the firing temperature of the insulating layer can be reduced. Reactionwith the dielectric materials due to diffusion can thus be prevented.

EXAMPLE 4

The multilayer substrate with inner capacitors of the fourth inventionis detailed below taking an example shown in FIG. 7.

FIG. 7 is a cross section of an example of a multilayer substrate withinner capacitors of the fourth invention. Since the structure of themultilayer substrate is the same as that of the third invention, theexplanation of the structure is omitted.

    ______________________________________                                               MgO         SiO.sub.2                                                                            CaO                                                 ______________________________________                                        .sub. A.sub.1                                                                          60            36      4                                              .sub. B.sub.2                                                                          36            60      4                                              C        30            60     10                                              .sub. E.sub.1                                                                          30            40     30                                              F        40            30     30                                              G        60            30     10                                              ______________________________________                                    

Points A₁, B₂, C, E₁, F and G and the lines connecting the points areexcluded from the composition area.

The insulating layer 1 is made by mixing ceramic material powdercomprising MgO and SiO₂ and CaO so that its composition is within thearea surrounded by the lines connecting points A₁, B₂, C, E₁, F and G asshown in FIG. 5 and so that the content of alumina in the insulatinglayer is restricted in the range between 1 and 15 weight % of the total(100 weight %) of MgO, SiO₂ and CaO, and by calcining the mixture at1000° to 1300° C. The calcined substance is pulverized into ceramicpowder and mixed with appropriate organic binders, dispersing agents,plasticizers and solvents to form slurry. The slurry is processed intogreen sheets by a known method such as the doctor blade method. Aplurality of the green sheets are laminated to form the insulating layer1.

The capacitor sections 2 and 2' are made as follows: the dielectricmaterial powder mainly comprising BaTiO₃ and the dielectric materialmainly comprising dielectric ceramics for temperature compensation arerespectively mixed and adjusted with organic binders and solvents toform two different types of slurry. Each type of slurry is processedinto green sheets by a known method such as the slip cast method. On theobtained dielectric green sheets, silver-palladium (Ag-Pd) alloy pasteis printed by the screen printing method according to the predeterminedelectrode patterns to form the electrode layers 5 and 5'.

To obtain continuity between the top and bottom surfaces of theinsulating layer 1 and capacitor sections 2 and 2', through-holesections 6 are formed by punching the green sheets of the insulating anddielectric layers. In the through-hole sections 6, the above-mentionedalloy paste is filled.

The above-mentioned green sheets of the insulating layer, the dielectriclayers mainly comprising barium titanate (BaTiO₃) and the dielectriclayer comprising dielectric ceramics for temperature compensationrespectively are laminated and pressed at heating. The obtainedlaminations are subjected to a binder burnout process at 200° to 400°C., then co-fired at 1220° to 1280° C. As a result, a multilayersubstrate with inner capacitor sections 2 and 2' is obtained.

The capacitor sections 2 and 2' are formed by laminating the twodifferent dielectric layers 4' mainly comprising dielectric ceramics fortemperature compensation on the top and bottom surfaces of thedielectric layer 4 mainly comprising barium titanate (BaTiO₃) with ahigh dielectric constant. When the layers are co-fired, the laminationcan prevent Ti and Ba (with high diffusion speed) from moving in thedielectric layers. This prevents the temperature characteristics of thecapacitor sections from being deteriorated.

Ag-Pd electric wiring conductor patterns are formed on the firedinsulating layer 1 by printing. Resistor patterns comprising rutheniumoxide (RuO₂) are also formed on the insulation layer 1 by printing. Theobtained substance is then fired at about 850° C. in the air to obtain amultilayer substrate with inner capacitors and the resistors 7.

When forming the electric wiring conductor patterns using a materialmainly comprising copper (Cu), a resistor material mainly comprisinglanthanum boride (LaB₆) and stannic oxide (SnO₂) is used to formresistor patterns. The resistor patterns are then fired at about 900° C.in an atmosphere of nitrogen. As a result, a multilayer substrate withinner capacitors is obtained in the same way as described above.

The various characteristics of the capacitor sections are notdeteriorated if the total amount of unavoidable impurities remaining inthe insulating layer 1, ferric oxide (Fe₂ O₃) and barium oxide (BaO),does not exceed 5 weight % of the total (100 weight %) of MgO, SiO₂, CaOand Al₂ O₃.

The fourth invention is detailed further taking an example of the fourthinvention.

Different types of ceramic material powder comprising MgO and SiO₂, CaOand Al₂ O₃ are mixed so that the composition of the insulating layer hasthe ratios indicated in Table 5 and calcined at 1100° to 1250° C. Thecalcined substance is pulverized to obtain the desired particle size.Appropriate organic binders and solvents are then added to the obtainedmaterial powder to form slurry. The slurry is processed by the doctorblade method to form a green sheet of 200 μm in thickness. The greensheet is then punched to obtain insulating sheets of 170 mm square.

The material powder mainly comprising barium titanate (BaTiO₃) and thematerial powder mainly comprising the dielectric material fortemperature compensation indicated in Table 6 are respectively mixedwith appropriate binders and solvents to form two different types ofslurry. The two types of slurry are processed by the slip cast method toform green sheets of 20 to 60 μm in thickness so that the capacitancevalues of the two capacitor sections can be set. The sheets are thenpunched and formed to dielectric sheets of 170 mm square.

On the two different types of the dielectric sheets, Ag-Pd alloy pasteis applied by a thick-film printing method such as the screen printingmethod to form electrode patterns of about 1 to 10 mm square dependingon the required electrostatic capacitance.

The through-hole sections formed in the insulating sheets and the twodifferent types of the dielectric sheets are filled with the Ag-Pd alloypaste by the screen printing method.

A plurality of the dielectric sheets comprising dielectric ceramics fortemperature compensation are sandwiched between the top and bottomsurfaces of the laminated dielectric sheets comprising barium titanateand pressed at heating. The obtained laminations are subjected to abinder burnout process at 200° to 400° C. in the air and fired in theair at the temperatures indicated in Table 6.

The evaluation samples made described above were checked forshort-circuit between the electrode layers of the high-capacitancecapacitor section and the temperature compensation capacitor sectionsusing an LCR meter. The electrostatic capacitance of thehigh-capacitance capacitor section was then measured at a frequency of 1kHz and at an input signal level of 1.0 Vrms using the LCR meteraccording to the JIS C 5102 standards. Relative permittivity (ε_(r)) wascalculated from the electrostatic capacitance. The electrostaticcapacitance of the temperature compensation capacitor section was alsomeasured at -55° C. to 125° C. and the change ratios of theelectrostatic capacitance values are calculated as temperaturecoefficients (TCC). In addition, the insulation resistance values of thecapacitor sections were measured 60 seconds after 25 V DC was applied tothe capacitor sections. The dielectric breakdown voltage values weremeasured across the terminals of each capacitor section when voltage wasapplied at a boosting speed of 100 V/second and in an moment the leakcurrent value exceeded 1.0 mA.

The evaluation samples were used for X-ray diffraction of the crystalphase of the insulating layer. The crystal phase was identifiedaccording to the X-ray diffraction pattern on the surface of eachevaluation sample. The thermal expansion coefficients of the insulatingand dielectric layers were obtained by measuring the average thermalexpansion coefficients in the temperature range between 40° and 800° C.using square rod test pieces measuring 3×3×40 mm and having the samecompositions as those of the corresponding evaluation samples andco-fired with the evaluation samples.

In addition, the green sheets having the same compositions as those ofthe above-mentioned evaluation samples of the insulating layer arepressed and laminated, then fired when the above-mentioned evaluationsamples were fired. The fired substance was formed into flat test piecesof 10 mm in width, 50 mm in length and 1.2 mm in thickness. Each testpiece was subjected to a three-point bending test by applying a load tothe center of the two support points (having a distance of 30 mm) of thetest piece at a speed of 0.5 mm per minute to measure the flexuralstrength of the insulating layer.

Tables 5 and 6 indicate the results of the measurement.

                                      TABLE 5                                     __________________________________________________________________________    Insulating layer                                                                                                             Thermal expansion                  Composition  Firing                        coefficient                                                                             Flexural             Sample                                                                            (weight %)   temperature                   40˜800°                                                                    strength             No. MgO                                                                              SiO.sub.2                                                                        CaO                                                                              Al.sub.2 O.sub.3                                                                  (°C.)                                                                         Crystal phase          (1/°C. ×                                                         10.sup.-6)                                                                              (kg/mm.sup.2)        __________________________________________________________________________    *1  60 33  7 2   1320   Mg.sub.2 SiO.sub.4, Ca.sub.2 MgSi.sub.2 O.sub.7,                              MgO                    12.2      --                   2, 3                                                                              59 34  7 5   1250   Mg.sub.2 SiO.sub.4, Ca.sub.2 MgSi.sub.2 O.sub.7,                              MgAl.sub.2 O.sub.4     11.8      20.5                 4, 5                                                                              59 32  9 2   1280   Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7     11.9      17.8                 *6  59 30 11 2   1340   Mg.sub.2 SiO.sub.4, Ca.sub.2 MgSi.sub.2 O.sub.7,                              MgAl.sub.2 O.sub.4, MgO                                                                              11.9      19.8                 *7  55 41  4 3   1280   Mg.sub.2 SiO.sub.4, Ca.sub.2 MgSi.sub.2 O.sub.7,                              MgAl.sub.2 O.sub.4     10.8      17.5                 8   54 41  5 2   1280   Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               11.9      19.2                 9, 10                                                                             56 39  5 5   1260   Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               11.7      21.5                 11, 12                                                                            56 34 10 5   1260   Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               11.9      20.0                 13, 14                                                                            51 44  5 2   1280   Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, MgAl.sub.2                                 O.sub.4                11.4      18.8                 *15 53 43  4 6   1240   Mg.sub.2 SiO.sub.4, Ca.sub.2 MgSi.sub.2 O.sub.7,                              MgAl.sub.2 O.sub.4     10.2      20.5                 16˜22                                                                       53 42  5 5   1250   Mg.sub.2 SiO.sub.4, Ca.sub.2 MgSi.sub.2 O.sub.7,                              MgAl.sub.2 O.sub.4     11.7      20.0                 23, 24                                                                            57 37  6 14  1220   Mg.sub.2 SiO.sub.4, Ca.sub.2 MgSi.sub.2 O.sub.7,                              MgAl.sub.2 O.sub.4     11.4      22.5                 25, 26                                                                            55 35 10 10  1230   Mg.sub.2 SiO.sub. 4, Ca.sub.2 MgSi.sub.2 O.sub.7,                             MgAl.sub.2 O.sub.4     11.6      21.0                 27˜33                                                                       52 34 14 5   1250   Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               12.0      19.9                 34, 35                                                                            46 49  5 2   1280   Mg.sub.2 SiO.sub.4, MgSiO.sub.3, Ca.sub.2                                     MgSi.sub.2 O.sub.7     11.3      18.5                 *36 46 45  9 1   1310   Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7     12.0      17.0                 37˜43                                                                       48 47  5 5   1250   Mg.sub.2 SiO.sub.4, MgSiO.sub.3, Ca.sub.2                                     MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               11.6      19.8                 44˜50                                                                       47 42 11 5   1250   Mg.sub.2 SiO.sub.4, Ca.sub.2 MgSi.sub.2 O.sub.7,                              MgAl.sub.2 O.sub.4     11.7      19.6                 51˜57                                                                       47 37 16 4   1250   Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               11.8      19.4                 58, 59                                                                            46 33 21 3   1260   Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               11.8      19.0                 60, 61                                                                            44 51  5 5   1260   Mg.sub.2 SiO.sub.4, MgSiO.sub.3, Ca.sub.2                                     MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               11.4      20.5                 62, 63                                                                            43 47 10 3   1250   Mg.sub.2 SiO.sub.4, MgSiO.sub.3, Ca.sub.2                                     MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               11.6      20.3                 64, 65                                                                            43 41 16 3   1250   Mg.sub.2 SiO.sub.4, Ca.sub.2 MgSi.sub.2 O.sub.7,                              MgAl.sub.2 O.sub.4     11.7      20.0                 66, 67                                                                            43 38 19 2   1280   Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7     11.8      18.8                 *68 49 44  7 15  1230   Mg.sub.2 SiO.sub.4, MgAl.sub.2 O.sub.4                                                               10.2      24.5                 69, 70                                                                            43 33 24 3   1230   Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               11.8      20.1                 71, 72                                                                            38 57  5 5   1240   Mg.sub.2 SiO.sub.4, MgSiO.sub.3, Ca.sub.2                                     MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               11.3      21.2                 73, 74                                                                            40 49 11 10  1230   Mg.sub.2 SiO.sub.4, MgSiO.sub.3, Ca.sub.2                                     MgSi.sub. 2 O.sub.7, MgAl.sub.2 O.sub.4                                                              11.5      21.5                 75, 76                                                                            40 38 22 10  1230   Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               11.6      21.3                 77˜83                                                                       38 33 29 4   1230   Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7     11.9      20.7                 *84 35 60  5 3   1250   Mg.sub.2 SiO.sub.4, MgSiO.sub.3, Ca.sub.2                                     MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               11.2      19.5                 85, 86                                                                            35 59  6 5   1230   Mg.sub.2 SiO.sub.4, MgSiO.sub.3, Ca.sub.2                                     MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               11.1      20.5                 87, 88                                                                            34 42 24 5   1230   Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               11.7      19.8                 89˜95                                                                       36 35 29 9   1220   Mg.sub.2 SiO.sub.4, CaMgSiO.sub.4, Ca.sub.2                                   MgSi.sub.2 O.sub.7, CaMgSi.sub.2 O.sub.8                                                             11.8      21.3                 *96 35 35 30 6   1240   Mg.sub.2 SiO.sub.4, CaMgSi.sub.2 O.sub.8,                                     Ca.sub.2 SiO.sub.4     12.0      15.8                 *97 30 53 17 5   1230   Mg.sub.2 SiO.sub.4, MgSiO.sub.3, Ca.sub.2                                     MgSi.sub.2 O.sub.7, MgAl.sub.2 O.sub.4                                                               11.5      20.2                 __________________________________________________________________________     Samples identified by the numbers marked * are excluded from the scope of     the claims of the fourth invention.                                      

                                      TABLE 6                                     __________________________________________________________________________    High-capacitance capacitor section                                                                        Temperature - compensation capacitor section         Dielec-                                                                            Thermal         Dielec-   Thermal            Dielec-                     tric expansion                                                                             Rela-                                                                             Insula-                                                                           tric      expansion      Insula-                                                                           tric                        material                                                                           coefficient of                                                                        tive                                                                              tion                                                                              break-                                                                            Dielectric                                                                          coefficient of                                                                        Temperature                                                                          tion                                                                              break-                   Sam-                                                                             (main                                                                              dielectric layer                                                                      permit-                                                                           resis-                                                                            down                                                                              material                                                                            dielectric layer                                                                      coefficient                                                                          resis-                                                                            down                     ple                                                                              com- 40˜800° C.                                                               tivity                                                                            tance                                                                             voltage                                                                           (main 40˜800° C.                                                               TCC    tance                                                                             voltage                  No.                                                                              ponent)                                                                            (1/°C. × 10.sup.-6)                                                      ε Γ                                                                 (Ω)                                                                         (V) component)                                                                          (1/°C. × 10.sup.-6)                                                      (ppm/°C.)                                                                     (Ω)                                                                         (V) Remarks              __________________________________________________________________________    *1 BaTiO.sub.3                                                                        12.4    --  --  --  Mg.sub.2 TiO.sub.4                                                                  10.5    --     --  --  Nonmeas-                                                                      urable               2  "    "       2500                                                                              >10.sup.10                                                                        >500                                                                              CaTiO.sub.3                                                                         12.0    N750   >10.sup.12                                                                        >1500                    3  "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N3     "   "                        4  "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N780   "   "                        *5 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N3     "   "                        *6 "    "       --  --  --  CaTiO.sub.3                                                                         12.0    --     --  --  Nonmeas-                                                                      urable               7  "    "       --  --  --  CaTiO.sub.3                                                                         12.0    N750   >10.sup.12                                                                        >1500                                                                             Partially                                                                     nonmeas-                                                                      urable               8  "    "       2500                                                                              >10.sup.10                                                                        >500                                                                              Mg.sub.2 TiO.sub.4                                                                  10.5    N3     "   "                        9  "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        10 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  11.0    N720   "   "                        11 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        12 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N3     "   "                        13 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        14 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N3     "   "                        *15                                                                              "    "       1500                                                                              10.sup.7                                                                            50                                                                              CaTiO.sub.3                                                                         12.0    N900   10.sup.9                                                                           1050                    16 "    "       2500                                                                              >10.sup.10                                                                        >500                                                                              BaTi.sub.4 O.sub.7                                                                  10.5    P2     >10.sup.12                                                                        >1500                    17 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        18 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N4     "   "                        19 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  11.0    N720   "   "                        20 "    "       "   "   "   La.sub.2 Ti.sub.2 O.sub.7                                                           10.6    N4     "   "                        21 "    "       "   "   "   SrTiO.sub.3                                                                         11.6    N2200  "   "                        22 "    "       "   "   "   Nd.sub.2 Ti.sub.2 O.sub.7                                                           10.7    P6     "   "                        23 BaTiO.sub.3                                                                        12.4    2500                                                                              >10.sup.10                                                                        >500                                                                              CaTiO.sub.3                                                                         12.0    N750   >10.sup.12                                                                        >1500                    24 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N3     "   "                        25 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        26 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N2     "   "                        27 "    "       "   "   "   BaTi.sub.4 O.sub.7                                                                  10.5    P3     "   "                        28 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        29 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N5     "   "                        30 "    "       "   "   "   Mg.sub. 2 TiO.sub.4                                                                 11.0    N710   "   "                        31 "    "       "   "   "   La.sub.2 Ti.sub.2 O.sub.7                                                           10.6    N5     "   "                        32 "    "       "   "   "   SrTiO.sub.3                                                                         11.6    N2100  "   "                        33 "    "       "   "   "   Nd.sub.2 Ti.sub.2 O.sub.7                                                           10.7    P6     "   "                        34 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        35 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  11.0    N710   "   "                        *36                                                                              "    "       --  --  --  CaTiO.sub.3                                                                         12.0    --     --  --  Nonmeas-                                                                      urable               37 "    "       2500                                                                              >10.sup.10                                                                        >500                                                                              BaTi.sub.4 O.sub.7                                                                  10.5    P3     >10.sup.12                                                                        >1500                    38 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        39 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N5     "   "                        40 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  11.0    N710   "   "                        41 "    "       "   "   "   La.sub.2 Ti.sub.2 O.sub.7                                                           10.6    N5     "   "                        42 "    "       "   "   "   SrTiO.sub.3                                                                         11.6    N2200  "   "                        43 "    "       "   "   "   Nd.sub.2 Ti.sub.2 O.sub.7                                                           10.7    P5     "   "                        44 "    "       "   "   "   BaTi.sub.4 O.sub.7                                                                  10.5    P3     "   "                        45 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        46 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N5     "   "                        47 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  11.0    N720   "   "                        48 BaTiO.sub.3                                                                        12.4    2500                                                                              >10.sup.10                                                                        >500                                                                              La.sub.2 Ti.sub.2 O.sub.7                                                           10.6    N5     >10.sup.12                                                                        > 1500                   49 "    "       "   "   "   SrTiO.sub.3                                                                         11.6    N2100  "   "                        50 "    "       "   "   "   Nd.sub.2 Ti.sub.2 O.sub.7                                                           10.7    P6     "   "                        51 "    "       "   "   "   BaTi.sub.4 O.sub.7                                                                  10.5    P4     "   "                        52 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N760   "   "                        53 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N6     "   "                        54 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  11.0    N720   "   "                        55 "    "       "   "   "   La.sub.2 Ti.sub.2 O.sub.7                                                           10.6    N6     "   "                        56 "    "       "   "   "   SrTiO.sub.3                                                                         11.6    N2200  "   "                        57 "    "       "   "   "   Nd.sub.2 Ti.sub.2 O.sub.7                                                           10.7    P6     "   "                        58 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N760   "   "                        59 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  11.0    N710   "   "                        60 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        61 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N5     "   "                        62 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        63 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  11.0    N720   "   "                        64 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        65 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N3     "   "                        66 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        67 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  11.0    N720   "   "                        *68                                                                              "    "       2050                                                                              10.sup.7                                                                             50                                                                             Mg.sub.2 TiO.sub.4                                                                  10.5    --     10.sup.9                                                                            800                                                                             Partially                                                                     nonmeas-                                                                      urable               69 "    "       2500                                                                              >10.sup.10                                                                        >500                                                                              CaTiO.sub.3                                                                         12.0    N750   >10.sup.12                                                                        >1500                    70 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  11.0    N720   "   "                        71 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        72 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N4     "   "                        73 BaTiO.sub.3                                                                        12.4    2500                                                                              >10.sup.10                                                                        >500                                                                              CaTiO.sub.3                                                                         12.0    N750   >10.sup.12                                                                        >1500                    74 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  11.0    N720   "   "                        75 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        76 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  11.0    N720   "   "                        77 "    "       "   "   "   BaTi.sub.4 O.sub.7                                                                  10.5    P3     "   "                        78 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        79 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N4     "   "                        80 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  11.0    N720   "   "                        81 "    "       "   "   "   La.sub.2 Ti.sub.2 O.sub.7                                                           10.6    N4     "   "                        82 "    "       "   "   "   SrTiO.sub.3                                                                         11.6    N2200  "   "                        83 "    "       "   "   "   Nd.sub.2 Ti.sub.2 O.sub.7                                                           10.7    P5     "   "                        *84                                                                              "    "       1980                                                                              10.sup.7                                                                            50                                                                              CaTiO.sub.3                                                                         12.0    N900   10.sup.9                                                                            900                    85 "    "       2500                                                                              >10.sup.10                                                                        >500                                                                              CaTiO.sub.3                                                                         12.0    N750   >10.sup.12                                                                        >1500                    86 "    "       "   "   "   Mg.sub. 2 TiO.sub.4                                                                 10.5    N5     "   "                        87 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N760   "   "                        88 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  11.0    N720   "   "                        89 "    "       "   "   "   BaTi.sub.4 O.sub.7                                                                  10.5    P4     "   "                        90 "    "       "   "   "   CaTiO.sub.3                                                                         12.0    N750   "   "                        91 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  10.5    N5     "   "                        92 "    "       "   "   "   Mg.sub.2 TiO.sub.4                                                                  11.0    N710   "   "                        93 "    "       "   "   "   La.sub.2 Ti.sub.2 O.sub.7                                                           10.6    N5     "   "                        94 "    "       "   "   "   SrTiO.sub.3                                                                         11.6    N2100  "   "                        95 "    "       "   "   "   Nd.sub.2 Ti.sub.2 O.sub.7                                                           10.7    P6     "   "                        *96                                                                              "    "       2150                                                                              10.sup.8                                                                          150 CaTiO.sub.3                                                                         12.0    N900   10.sup.10                                                                         1000                     *97                                                                              "    "       2200                                                                              10.sup.9                                                                          350 CaTiO.sub.3                                                                         12.0    N900   10.sup.10                                                                         1000                     __________________________________________________________________________     Samples identified by the numbers marked * are excluded from the scope of     the claims of the fourth invention.                                      

With the multilayer substrate with inner capacitors of the fourthinvention, the insulating layer mainly comprising magnesia, silica,calcia and alumina being superior in high-frequency insulationperformance can be co-fired at a low temperature with the dielectriclayer comprising barium titanate (BaTiO₃) with a high dielectricconstant and the dielectric layer mainly comprising various dielectricceramics for temperature compensation without causing reaction betweenthe two different dielectric layers. In addition, the thermal expansioncoefficient of the insulating layer can be set very close to those ofthe dielectric layers. The substrate can thus include both the capacitorsection with high electrostatic capacitance and the temperaturecompensation capacitor section with superior temperaturecharacteristics, both of which are superior in the insulation resistanceand dielectric breakdown voltage without causing cracks in thedielectric layer. Furthermore, the insulating layer can be strengthenedand the electric wiring conductor layers can be firmly coated on theinsulating layer. As a result, the invention can offer a multilayersubstrate with inner capacitors that is miniaturized and high indensity, ideally suited for hybrid substrates.

It can be easily understood that the compositions of the dielectric andinsulating layers and the objects, functions and effects of the genusinvention are based on the unification of the first to fourth inventionsdetailed above. Therefore, without explaining the genus invention thatis defined by claim 1 and FIGS. 1 and 6, the details of the genusinvention will be obvious from the explanations of the first to fourthinventions.

We claim:
 1. A multilayer substrate with inner capacitors comprising adielectric layer sandwiched between upper and lower insulating layers, acouple of printed electrodes in desired patterns within the thickness ofthe dielectric layer so as to form each capacitor at the portion of saiddielectric layer corresponding to said electrodes, and a couple ofleading terminals on one surface of said insulating layer, whichcommunicate with said electrodes, said multilayer substrate beingcharacterized in that said dielectric layer is composed of a ceramiccomposition mainly comprising MTiO₃ -based ceramics (M represents one orseveral of Ba, Ca, Mg, La, Sr and Nd) and that said insulating layer iscomposed of a ceramic composition mainly comprising MgO-SiO₂ -CaO-basedceramics, which is defined by an area surrounded by the lines connectingpoints A, B, C, D, E, F and G as shown in FIG. 1 and listed below,wherein X, Y and Z respectively represent weight percent values of MgO,SiO₂ and CaO at points A, B, C, D, E, F and G:

    ______________________________________                                               X            Y     Z                                                   ______________________________________                                        A        60             40     0                                              B        40             60     0                                              C        30             60    10                                              D        30             50    20                                              E        20             50    30                                              F        40             30    30                                              G        60             30    10                                              ______________________________________                                    


2. A multilayer substrate with inner capacitors according to claim 1,wherein said dielectric layer is composed of a ceramic compositionmainly comprising BaTiO₃ and said insulating layer is mainly composed ofa ceramic composition mainly comprising MgO-SiO₂ -CaO-based ceramics,which is defined by an area surrounded by the lines connecting pointsA₁, B₁, E, F and G as shown in FIG. 2 and listed below:

    ______________________________________                                               X            Y     Z                                                   ______________________________________                                        A.sub.1  60             36     4                                              B.sub.1  46             50     4                                              E        20             50    30                                              F        40             30    30                                              G        60             30    10                                              ______________________________________                                    


3. A multilayer substrate with inner capacitors according to claim 2,wherein said insulating layer includes at least one crystal phase offorsterite (Mg₂ SiO₄), monticellite (CaMgSiO₄) or akermanite (Ca₂ MgSi₂O₇).
 4. A multilayer substrate with inner capacitors according to claim2, wherein said dielectric layer and said insulating layers, betweenwhich said capacitor section being composed of said dielectric layerportions and electrode layers are sandwiched, can be co-fired.
 5. Amultilayer substrate with inner capacitors according to claim 1, whereinsaid dielectric layer is composed of a ceramic composition mainlycomprising MTiO₃ -based ceramics (M represents one or several of Ca, Mg,La, Sr and Nd) and said insulating layer is composed of a ceramiccomposition mainly comprising MgO-SiO₂ -CaO-based ceramics, which isdefined by an area surrounded by the lines connecting points A, B, C,E₁, F and G as shown in FIG. 3 and listed below:

    ______________________________________                                                X           Y     Z                                                   ______________________________________                                        A         60            40     0                                              B         40            60     0                                              C         30            60    10                                              .sup. E.sub.1                                                                           30            40    30                                              F         40            30    30                                              G         60            30    10                                              ______________________________________                                    


6. A multilayer substrate with inner capacitors according to claim 5,wherein said insulating layer includes at least one crystal phase offorsterite (Mg₂ SiO₄), enstatite (MgSiO₃), monticellite (CaMgSiO₄) orakermanite (Ca₂ MgSi₂ O₇).
 7. A multilayer substrate with innercapacitors according to claim 5, wherein said dielectric layer and saidinsulating layers, between which said capacitor section being composedof said dielectric layer portions and electrode layers are sandwiched,can be co-fired.
 8. A multilayer substrate with inner capacitorsaccording to claim 1, wherein said dielectric layer is composed of aceramic composition mainly comprising MTiO₃ -based ceramics (Mrepresents one or several of Ba, Ca, Mg, La, Sr and Nd) and saidinsulating layer is composed of a ceramic composition mainly comprisingMgO-SiO₂ -CaO-based ceramics, which is defined by an area surrounded bythe lines connecting points A₁, B₁, D, E₁, F and G as shown in FIG. 4and listed below:

    ______________________________________                                                X           Y     Z                                                   ______________________________________                                        .sup. A.sub.1                                                                           60            36     4                                              .sup. B.sub.1                                                                           46            50     4                                              D         30            50    20                                              .sup. E.sub.1                                                                           30            40    30                                              F         40            30    30                                              G         60            30    10                                              ______________________________________                                    


9. A multilayer substrate with inner capacitors according to claim 8,wherein said insulating layer includes at least one crystal phase offorsterite (Mg₂ SiO₄), merwinite (Ca₃ MgSi₂ O₈), monticellite(CaMgSiO₄), akermanite (Ca₂ MgSi₂ O₇) or enstatite (MgSiO₃).
 10. Amultilayer substrate with inner capacitors according to claim 9, whereinsaid dielectric layer and said insulating layers, between which saidcapacitor section being composed of said dielectric layer portions andelectrode layers are sandwiched, can be co-fired.
 11. A multilayersubstrate with inner capacitors according to claim 10, wherein saidinsulating layer includes at least one crystal phase of forsterite (Mg₂SiO₄), merwinite (Ca₃ MgSi₂ O₈), monticellite (CaMgSiO₄), akermanite(Ca₂ MgSi₂ O₇), enstatite (MgSiO₃) or spinel (MgAl₂ O₄).
 12. Amultilayer substrate with inner capacitors according to claim 10,wherein said insulating layer is composed of a ceramic compositioncomprising MgO-SiO₂ -CaO-based ceramics, which is defined by an areasurrounded by the lines connecting points A₁ ', B₂ ', C', E₁ ', F' andG' as shown in FIG. 5 and listed below, and said insulating layer alsocomprises Al₂ O₃ ranging between 2 and 15 weight % of the total (100weight %) of MgO, SiO₂ and CaO:

    ______________________________________                                                X           Y     Z                                                   ______________________________________                                        A.sub.1 ' 55            40     5                                              B.sub.2 ' 45            50     5                                              C'.sup.   40            50    10                                              E.sub.1 ' 40            40    20                                              F'.sup.   45            35    20                                              G'.sup.   55            35    10                                              ______________________________________                                    


13. A multilayer substrate with inner capacitors according to claim 1,wherein said dielectric layer is composed of a ceramic compositionmainly comprising MTiO₃ -based ceramics (M represents one or several ofBa, Ca, Mg, La, Sr and Nd) and said insulating layer is composed of aceramic composition comprising MgO-SiO₂ -CaO-based ceramics, which isdefined by an area surrounded by the lines connecting points A₁, B₂, C,E₁, F and G as shown in FIG. 5 and listed below, and said insulatinglayer also comprises Al₂ O₃ ranging between 1 and 15 weight % of thetotal (100 weight %) of MgO, SiO₂ and CaO, with points A₁, B₂, C, E₁, F₁and G and the lines connecting the points excluded from the area:

    ______________________________________                                                X           Y     Z                                                   ______________________________________                                        .sup. A.sub.1                                                                           60            36     4                                              .sup. B.sub.2                                                                           36            60     4                                              C         30            60    10                                              .sup. E.sub.1                                                                           30            40    30                                              F         40            30    30                                              G         80            30    10                                              ______________________________________                                    


14. A multilayer substrate with inner capacitors according to claim 10or 13, wherein said dielectric layer and said insulating layers, betweenwhich said capacitor section being composed of said dielectric layerportions and electrode layers are sandwiched, can be co-fired.